systematic review search string

University of Michigan Library
Research Guides

Systematic Reviews

Search Strategy
Work with a Search Expert
Covidence Review Software
Types of Reviews
Evidence in a Systematic Review
Information Sources

Developing an Answerable Question

Creating a search strategy, identifying synonyms & related terms, keywords vs. index terms, combining search terms using boolean operators, a sr search strategy, search limits.

Managing Records
Selection Process
Data Collection Process
Study Risk of Bias Assessment
Reporting Results
For Search Professionals

Validated Search Filters

Depending on your topic, you may be able to save time in constructing your search by using specific search filters (also called "hedges") developed & validated by researchers in the Health Information Research Unit (HiRU) of McMaster University, under contract from the National Library of Medicine. These filters can be found on

PubMed’s Clinical Queries & Health Services Research Queries pages
Ovid Medline’s Clinical Queries filters or here
Embase & PsycINFO
EBSCOhost’s main search page for CINAHL (Clinical Queries category)
HiRU’s Nephrology Filters page
American U of Beirut, esp. for " humans" filters .
Countway Library of Medicine methodology filters
InterTASC Information Specialists' Sub-Group Search Filter Resource
SIGN (Scottish Intercollegiate Guidelines Network) filters page

Why Create a Sensitive Search?

In many literature reviews, you try to balance the sensitivity of the search (how many potentially relevant articles you find) & specificit y (how many definitely relevant articles you find ), realizing that you will miss some. In a systematic review, you want a very sensitive search: you are trying to find any potentially relevant article. A systematic review search will:

contain many synonyms & variants of search terms
use care in adding search filters
search multiple resources, databases & grey literature, such as reports & clinical trials

PICO is a good framework to help clarify your systematic review question.

P - Patient, Population or Problem: What are the important characteristics of the patients &/or problem?

I - Intervention: What you plan to do for the patient or problem?

C - Comparison: What, if anything, is the alternative to the intervention?

O - Outcome: What is the outcome that you would like to measure?

Beyond PICO: the SPIDER tool for qualitative evidence synthesis.

5-SPICE: the application of an original framework for community health worker program design, quality improvement and research agenda setting.

A well constructed search strategy is the core of your systematic review and will be reported on in the methods section of your paper. The search strategy retrieves the majority of the studies you will assess for eligibility & inclusion. The quality of the search strategy also affects what items may have been missed. Informationists can be partners in this process.

For a systematic review, it is important to broaden your search to maximize the retrieval of relevant results.

Use keywords: How other people might describe a topic?

Identify the appropriate index terms (subject headings) for your topic.

Index terms differ by database (MeSH, or Medical Subject Headings , Emtree terms , Subject headings) are assigned by experts based on the article's content.
Check the indexing of sentinel articles (3-6 articles that are fundamental to your topic). Sentinel articles can also be used to test your search results.

Include spelling variations (e.g., behavior, behaviour ).

Both types of search terms are useful & both should be used in your search.

Keywords help to broaden your results. They will be searched for at least in journal titles, author names, article titles, & article abstracts. They can also be tagged to search all text.

Index/subject terms help to focus your search appropriately, looking for items that have had a specific term applied by an indexer.

Boolean operators let you combine search terms in specific ways to broaden or narrow your results.

An example of a search string for one concept in a systematic review.

In this example from a PubMed search, [mh] = MeSH & [tiab] = Title/Abstract, a more focused version of a keyword search.

A typical database search limit allows you to narrow results so that you retrieve articles that are most relevant to your research question. Limit types vary by database & include:

Article/publication type
Publication dates

In a systematic review search, you should use care when applying limits, as you may lose articles inadvertently. For more information, see, particularly regarding language & format limits. Cochrane 2008 6.4.9

Systematic Reviews

Introduction
Review Process: Step by Step
1. Planning a Review
2. Defining Your Question & Criteria
3. Standards & Protocols

Designing Your Search Strategy

Search strategy checklists, pre-search tips, search strategies: filters & hedges, search terms, search strategies: and/or, phrase searching & truncation.

5. Locating Published Research
6. Locating Grey Literature
7. Managing & Documenting Results
8. Selecting & Appraising Studies
9. Extracting Data
10. Writing a Systematic Review
Tools & Software
Guides & Tutorials
Accessing Resources
Research Assistance

A well designed search strategy is essential to the success of your systematic review. Your strategy should be specific, unbiased, reproducible and will typically include subject headings along with a range of keywords/phrases for each of your concepts.

Your searches should be designed to capture as many studies as possible that meet your criteria.

Chapter 4 of the Cochrane Handbook for Systematic Reviews of Interventions provides detailed guidance for searching and study selection; see Supplement 3.8 Adapting search strategies across databases / sources for translating your search across databases.

Systematic Reviews: Constructing a Search Strategy and Searching for Evidence from the Joanna Briggs Institute provides step-by-step guidance using PubMed as an example database.

General Steps:

Locate previous/ relevant searches
Identify your databases
Develop your search terms and design search
Evaluate and modify your search
Document your search ( PRISMA-S Checklist)
Translate your search for other databases
Step by Step Systematic Review Search Checklist from MD Anderson Center Library
PRESS Peer Review Checklist for Search Strategies

Conduct a preliminary set of scoping searches in various databases to test out your search terms (keywords and subject headings) and locate additional terms for your concepts.

Try building a "gold set" of relevant references to help you identify search terms. Sources for this gold set may include:

Recommended key papers
Papers by known authors in the field
Results of preliminary searches from key databases such
Reviewing references and "cited by" articles lists for key papers
Articles that have been published in authoritative journals

Hedges/ Filters

PubMed Special Queries

Hedges are search strings created by experts to help you retrieve specific types of studies or topics; a hedge will filter your results by adding specific search terms, or specific combinations of search terms, to your search.

Hedges can be good starting points but you may need to modify the search string to fit your research. Resources for hedges:

University of Texas, School of Public Health (study type)
McMaster University Health Information Research Unit
The InterTASC Information Specialists' Sub-Group Search Filter Resource
Pubmed Search Strategies blog
PubMed Special Queries Topic-Specific PubMed Queries; includes keyword and search strategy examples.

Example: Health Disparities & Minority Health Search Strategies

Subject Headings
Keywords Vs. Subject Headings
Locating Subject Headings
Medical Subject Headings (MeSH)
Keyword & Subject Headings Logic Grid

You can use your PICOTS concepts as preliminary search terms. The important terms in this question:

In adults , is screening for depression and feedback of results to providers more effective than no screening and feedback in improving outcomes of major depression in primary care settings?

...might include:

Major depression

Primary Care

(From Lackey, M. (2013). Systematic reviews: Searching the literature [PowerPoint slides]. Retrieved from http://guides.lib.unc.edu/ld.php?content_id=258919 )

Your search will include both keywords and subject headings. Controlled vocabulary systems, such as the Medical Subject Headings (MeSH) or Library of Congress Subject Headings (LCSH) , use pre-set terms that are used to tag resources on similar subjects. See boxes below for more information on finding and using subject terms.

Not all databases will have subject heading searching and for those that do, the subject heading categories may differ between databases. This is because databases classify articles using different criteria.

Using the keywords from our example, here are some MeSH terms for:

Adults : Adult (A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.)

Screening : Mass Screening (Organized periodic procedures performed on large groups of people for the purpose of detecting disease.)

Major depression : Depressive Disorder, Major (Marked depression appearing in the involution period and characterized by hallucinations, delusions, paranoia, and agitation.)

Here is a LCSH subject term for:

Depression : Depression, mental (Dejection ; Depression, Unipolar ; Depressive disorder ; Depressive psychoses ; Melancholia ; Mental depression ; Unipolar depression)

Most EBSCO databases have a tool to help you discover subject terms . See Academic Search Complete > Subject Terms and Academic Search Complete > Subject Terms: Thesaurus
Most ProQuest databases have a tool to help you discover subject terms: See PsycInfo > Thesaurus
When you find a useful article, look at the article's Subject Headings (or Subject or Subject Terms) , and record them as possible terms to use in a subject term search.

Here is an example of the subject terms listed for a systematic review found in PsycINFO, " Primary care screening for and treatment of depression in pregnant and postpartum women: Evidence report and systematic review for the US Preventive Services Task Force " (2016).

MeSH are standardized terms that describe the main concepts of PubMed/MedLine articles. Searching with MeSH can increase the precision of your search by providing a consistent way to retrieve articles that may use different terminology or spelling variations.

Note: new articles will not have MeSH terms; the indexing process may take up to a few weeks for newly ingested articles.

Use the MeSH database to locate and build a search using MeSH.

To search the MeSH database:

Search for 1 concept at a time.
If you do not see a relevant MeSH in the results, search again with a synonym or related term.
Click on the MeSH term to view to the complete record, subheadings, broader and narrower terms.

Build a search from the results list or from the MeSH term record to specify subheadings.

Select the box next to the MeSH term or subheadings that you wish to search and click Add to Search Builder.
You may need to switch AND to OR , depending on how you would like to combine terms.
Repeat the above steps to add additional MeSH terms. When your search is ready, click Search PubMed.

Logic Grid with Keywords and Index Terms or Subject Headings from Systematic Reviews: Constructing a Search Strategy and Searching for Evidence.

Bhuiyan, M. U., Stiboy, E., Hassan, M. Z., Chan, M., Islam, M. S., Haider, N., Jaffe, A., & Homaira, N. (2021). Epidemiology of COVID-19 infection in young children under five years: A systematic review and meta-analysis. Vaccine , 39 (4), 667–677. https://doi.org/10.1016/j.vaccine.2020.11.078

Boolean Logic: AND, OR, NOT
Phrase Searching " "
Truncation *
Proximity Searching

AND, OR, NOT

Join together search terms in a logical manner.

AND - narrows searches, used to join dissimilar terms OR - broadens searches, used to join similar terms

NOT - removes results containing specified keywords

#1 "major depression" AND "primary care"

#2 screen* OR feedback

#3 (screen* OR feedback)

AND “major depression”

AND “primary care”

"major depression" NOT suicide

" " To search for specific phrases, enclose them in quotation marks . The database will search for those words together in that order.

“ primary care ”

“ major depression ”

Truncate a word in order to search for different forms of the same word. Many databases use the asterisk * as the truncation symbol.

Add the truncation symbol to the word screen * to search for screen, screens, screening, etc.

You do have to be careful with truncation. If you add the truncation symbol to the word minor* , the database will search for minor, minors, minority, minorities, etc.

Not all databases support proximity searching. You can use these strategies in ProQuest databases such as Sociological Abstracts .

pre/# is used to search for terms in proximity to each other in a specific order; # is replaced with the number of words permitted between the search terms.

Sample Search: parent* pre/2 educational (within 2 words & in order )

This would retrieve articles with no more than two words between parent* and educational (in this order) e.g. " Parent practices and educational achievement" OR " Parents on Educational Attainment" OR " Parental Values, Educational Attainment" etc.

w/# is used to search for terms in proximity to each other in any order ; # is replaced with the number of words permitted between the search terms.

Sample Search: parent* w/3 educational (within 3 words & in any order )

This would retrieve articles with no more than three words between parent* and educational (in any order) e.g. "Educational practices of parents" OR "Parents value motivation and education" OR "Educational attainments of Latino parents"
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How to write a search strategy for your systematic review

Home | Blog | How To | How to write a search strategy for your systematic review

Practical tips to write a search strategy for your systematic review

With a great review question and a clear set of eligibility criteria already mapped out, it’s now time to plan the search strategy. The medical literature is vast. Your team plans a thorough and methodical search, but you also know that resources and interest in the project are finite. At this stage it might feel like you have a mountain to climb.

The bottom line? You will have to sift through some irrelevant search results to find the studies that you need for your review. Capturing a proportion of irrelevant records in your search is necessary to ensure that it identifies as many relevant records as possible. This is the trade-off of precision versus sensitivity and, because systematic reviews aim to be as comprehensive as possible, it is best to favour sensitivity – more is more.

By now, the size of this task might be sounding alarm bells. The good news is that a range of techniques and web-based tools can help to make searching more efficient and save you time. We’ll look at some of them as we walk through the four main steps of searching for studies:

Decide where to search
Write and refine the search
Run and record the search
Manage the search results

Searching is a specialist discipline and the information given here is not intended to replace the advice of a skilled professional. Before we look at each of the steps in turn, the most important systematic reviewer pro-tip for searching is:

Pro Tip – Talk to your librarian and do it early!

1. decide where to search .

It’s important to come up with a comprehensive list of sources to search so that you don’t miss anything potentially relevant. In clinical medicine, your first stop will likely be the databases MEDLINE , Embase , and CENTRAL . Depending on the subject of the review, it might also be appropriate to run the search in databases that cover specific geographical regions or specialist areas, such as traditional Chinese medicine.

In addition to these databases, you’ll also search for grey literature (essentially, research that was not published in journals). That’s because your search of bibliographic databases will not find relevant information if it is part of, for example:

a trials register
a study that is ongoing
a thesis or dissertation
a conference abstract.

Over-reliance on published data introduces bias in favour of positive results. Studies with positive results are more likely to be submitted to journals, published in journals, and therefore indexed in databases. This is publication bias and systematic reviews seek to minimise its effects by searching for grey literature.

2. Write and refine the search

Search terms are derived from key concepts in the review question and from the inclusion and exclusion criteria that are specified in the protocol or research plan.

Keywords will be searched for in the title or abstract of the records in the database. They are often truncated (for example, a search for therap* to find therapy, therapies, therapist). They might also use wildcards to allow for spelling variants and plurals (for example, wom#n to find woman and women). The symbols used to perform truncation and wildcard searches vary by database.

Index terms

Using index terms such as MeSH and Emtree in a search can improve its performance. Indexers with subject area expertise work through databases and tag each record with subject terms from a prespecified controlled vocabulary.

This indexing can save review teams a lot of time that would otherwise be spent sifting through irrelevant records. Using index terms in your search, for example, can help you find the records that are actually about the topic of interest (tagged with the index term) but ignore those that contain only a brief mention of it (not tagged with the index term).

Indexers assign terms based on a careful read of each study, rather than whether or not the study contains certain words. So the index terms enable the retrieval of relevant records that cannot be captured by a simple search for the keyword or phrase.

Use a combination

Relying solely on index terms is not advisable. Doing so could miss a relevant record that for some reason (indexer’s judgment, time lag between a record being listed in a database and being indexed) has not been tagged with an index term that would enable you to retrieve it. Good search strategies include both index terms and keywords.

Let’s see how this works in a real review! Figure 2 shows the search strategy for the review ‘Wheat flour fortification with iron and other micronutrients for reducing anaemia and improving iron status in populations’. This strategy combines index terms and keywords using the Boolean operators AND, OR, and NOT. OR is used first to reach as many records as possible before AND and NOT are used to narrow them down.

Lines 1 and 2: contain MeSH terms (denoted by the initial capitals and the slash at the end).
Line 3: contains truncated keywords (‘tw’ in this context is an instruction to search the title and abstract fields of the record).
Line 4: combines the three previous lines using Boolean OR to broaden the search.
Line 11: combines previous lines using Boolean AND to narrow the search.
Lines 12 and 13: further narrow the search using Boolean NOT to exclude records of studies with no human subjects.

Writing a search strategy is an iterative process. A good plan is to try out a new strategy and check that it has picked up the key studies that you would expect it to find based on your existing knowledge of the topic area. If it hasn’t, you can explore the reasons for this, revise the strategy, check it for errors, and try it again!

3. Run and record the search

Because of the different ways that individual databases are structured and indexed, a separate search strategy is needed for each database. This adds complexity to the search process, and it is important to keep a careful record of each search strategy as you run it. Search strategies can often be saved in the databases themselves, but it is a good idea to keep an offline copy as a back-up; Covidence allows you to store your search strategies online in your review settings.

The reporting of the search will be included in the methods section of your review and should follow the PRISMA guidelines. You can download a flow diagram from PRISMA’s website to help you log the number of records retrieved from the search and the subsequent decisions about the inclusion or exclusion of studies. The PRISMA-S extension provides guidance on reporting literature searches.

It is very important that search strategies are reproduced in their entirety (preferably using copy and paste to avoid typos) as part of the published review so that they can be studied and replicated by other researchers. Search strategies are often made available as an appendix because they are long and might otherwise interrupt the flow of the text in the methods section.

4. Manage the search results

Once the search is done and you have recorded the process in enough detail to write up a thorough description in the methods section, you will move on to screening the results. This is an exciting stage in any review because it’s the first glimpse of what the search strategies have found. A large volume of results may be daunting but your search is very likely to have captured some irrelevant studies because of its high sensitivity, as we have already seen. Fortunately, it will be possible to exclude many of these irrelevant studies at the screening stage on the basis of the title and abstract alone 😅.

Search results from multiple databases can be collated in a single spreadsheet for screening. To benefit from process efficiencies, time-saving and easy collaboration with your team, you can import search results into a specialist tool such as Covidence. A key benefit of Covidence is that you can track decisions made about the inclusion or exclusion of studies in a simple workflow and resolve conflicting decisions quickly and transparently. Covidence currently supports three formats for file imports of search results:

EndNote XML
PubMed text format
RIS text format

If you’d like to try this feature of Covidence but don’t have any data yet, you can download some ready-made sample data .

And you’re done!

There is a lot to think about when planning a search strategy. With practice, expert help, and the right tools your team can complete the search process with confidence.

This blog post is part of the Covidence series on how to write a systematic review.

[1] Witt KG, Hetrick SE, Rajaram G, Hazell P, Taylor Salisbury TL, Townsend E, Hawton K. Pharmacological interventions for self‐harm in adults . Cochrane Database of Systematic Reviews 2020, Issue 12. Art. No.: CD013669. DOI: 10.1002/14651858.CD013669.pub2. Accessed 02 February 2021

Laura Mellor. Portsmouth, UK

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Combining keywords with Boolean operators

Conducting a good search requires a bit more than just putting single search terms in a search bar. In order to retrieve specific and targeted information about your topic, you need to logically combine search terms with each other. To do that, you use Boolean operators:

AND: if you are looking for references in which both search terms appear;
OR: if you are looking for references containing at least one of the search terms;
NOT: if you are looking for references in which a particular search term does not occur.

Note: Be careful when using NOT; it may exclude relevant articles by inadvertently (false negatives). A suggestion here is: run the search with and without the NOT, and see the difference by comparing the results in your Search History: how many results are omitted? Are the results that are omitted relevant to your search or not? Based on this, you can decide whether or not the NOT is a useful addition to your search string.

How to build a search string:

collect search terms and keywords by subtopic;
combine them with OR;
place the keywords between parentheses;
put an AND between the subtopics

Generic example: (... OR ... OR ... OR ... OR ...) AND (... OR ... OR ... OR ...) AND (... OR ... OR ... OR ... OR ...)

With this, you have created a basic search string that you can use for multiple databases. For some databases, you can fine-tune the search string by adding thesaurus terms and/or search fields (see below).

More tips and suggestions

Several techniques exist for fine-tuning your search string. Note that databases often have their own 'rules'. It is advisable to check per database which 'rules' apply to the syntax of your query. These can be found in the HELP or FAQ section of the database in question.

Exact word combination If you only want to find search results that contain the search terms in exactly that order, place your search terms inside double quotation marks ("....."), e.g. "Attention Deficit Hyperactivity Disorder."

Pro tip: an exact word combination is actually a strict version of the Boolean AND operator, where the search terms must also occur in that particular order. Therefore, the order of the search terms is not arbitrary, but set by you.

Truncation is a technique that can be used to expand your search; the end of a search term is replaced by a truncation mark, also known as a wildcard. Doing so allows you to efficiently find word variants and thus expand your search. For example:

child* = child, children, childhood, childhood, child-friendly, childs, child-like
industr* = industry, industries, industrial
genetic* = genetic, genetics

Truncation symbols may vary by database, but frequently used symbols include *, !, ? or #.

A wildcard is a symbol that replaces a letter of a word. This is especially useful when a word can be spelled several ways (but mean the same thing), such as in a British variant as an American variant. For example

wom!n = woman, women
colo?r = color, color
latin?= latina, latinx, latine, latino, latines

Search fields When you enter your basic search string into the search bar, your search terms will generally be checked to see if they appear anywhere in the text of the article. This can potentially create a lot of noise. Limiting your search to a to specific search fields will make it more focused. Advanced Search allows you to search only certain fields, e.g. title and/or abstract, keywords, or subject.

For example, "language development disorder"[abstract] AND "primary school"[abstract] AND "teaching materials"[abstract].

Note that each database has its own configuration and search fields, so always tailor your search to the database!

Minilecture Smart search

Useful links and resources

Useful links

See this link for a great visualization of a search string from a scoping paper .

If you have questions, please contact the Information Specialist Research of your research center , or go to support & contact for more information and advice.

[anchornavigation]

University of Tasmania, Australia

Systematic reviews for health: building search strategies.

Handbooks / Guidelines for Systematic Reviews
Standards for Reporting
Registering a Protocol
Tools for Systematic Review
Online Tutorials & Courses
Books and Articles about Systematic Reviews
Finding Systematic Reviews
Critical Appraisal
Library Help
Bibliographic Databases
Grey Literature
Handsearching
Citation Tracking
1. Formulate the Research Question
2. Identify the Key Concepts
3. Develop Search Terms - Free-Text
4. Develop Search Terms - Controlled Vocabulary
5. Search Fields
6. Phrase Searching, Wildcards and Proximity Operators
7. Boolean Operators
8. Search Limits
9. Pilot Search Strategy & Monitor Its Development
10. Final Search Strategy
11. Adapt Search Syntax
Documenting Search Strategies
Handling Results & Storing Papers

Building Search Strategies

Building search strategies is part of the search for studies step..

This tab offers a step-by-step guide to developing a search strategy for a systematic review. The theoretical explanation for each of the steps (left column) is supplemented with an example (right column).

It is recommended to work through the steps sequentially, starting with Step 1 .

Steps of Building Search Strategies

These are the steps required when developing a comprehensive search strategy for a systematic review:

1. Formulate the research question

2. Identify the key concepts

3. Develop search terms - free-text terms

4. Develop search terms - controlled vocabulary terms

5. Search fields

6. Phrase searching, wildcards and proximity operators

7. Boolean operators

8. Search limits

9. Pilot search strategy and monitor its development

10. Final search strategy

11. Adapt search syntax for different databases

Templates / Helpsheets

Template for Systematic Review search

To illustrate each step for developing a search strategy, the example used in the following 11 steps is (with a slight adaptation):

Aromataris, E & Riitano, D 2014, 'Systematic reviews: Constructing a search strategy and searching for evidence', AJN The American Journal of Nursing , vol. 114, no. 5, pp. 49-56.

Additional Resources

A subsection of the Evidence-Based Information Special Interest Group (EBI-SIG) with the European Association of Health Information and Libraries (EAHIL) are working on a project to create living open access Library of Search Strategy Resources :

Library of Search Strategy Resources (LSSR)

SuRe Info is a web resource that provides research-based information relating to information retrieval aspects of producing systematic reviews. The resource is kept up-to-date by an international team of experienced information specialists.

SuRe Info - Summarised Research in Information Retrieval for HTA

Other Australian universities have developed extensive guides on building search strategies:

Plan your search strategy (University of Adelaide)
Systematic reviews: Search strategy (University of Newcastle)

These videos from the Medical Library at Yale University outline how to build search strategies for a systematic review:

Systematic Searches #4: Building Search Strategies (Part I)
Systematic Searches #5: Building Search Strategies (Part II)
Systematic Searches #6: Building Search Strategies (Part III)
Systematic Searches #7: Building Search Strategies (Part IV)
Systematic Searches #8: Building Search Strategies (Part V)
Systematic Searches #9: Using Filters and Hedges

Need More Help? Book a consultation with a Learning and Research Librarian or contact [email protected] .

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Next: 1. Formulate the Research Question >>
Last Updated: May 8, 2024 1:29 PM
URL: https://utas.libguides.com/SystematicReviews

Systematic Review

Library Help
What is a Systematic Review (SR)?
Steps of a Systematic Review
Framing a Research Question

Developing a Search Strategy

Searching the Literature
Managing the Process
Meta-analysis
Publishing your Systematic Review

Workshop materials

PICO Worksheet
Search Strategy Example
Search Strategy Presentation Slides
Search strings for demo

Find step-by-step instructions on how to develop a search strategy on p. 44

Errors in search strategies

Salvador-Oliván, J. A., Marco-Cuenca, G., & Arquero-Avilés, R. (2019). Errors in search strategies used in systematic reviews and their effects on information retrieval . Journal of the Medical Library Association : JMLA , 107 (2), 210–221. https://doi.org/10.5195/jmla.2019.567 .

Search Term Harvesting
Text Mining Tools
Search Filters / Hedges
Documenting
Blogs & Discussion Lists

Translating search strategies across databases

ChatGPT Ask ChatGPT using this prompt, "Covert this search into terms appropriate for the [name] database." Further reading: Wang, S., Scells, H., Koopman, B., & Zuccon, G. (2023). Can ChatGPT write a good boolean query for systematic review literature search?. arXiv preprint arXiv:2302.03495.
LitSonar Use the Help section for further guidance on how to use this tool (https://litsonar.com/help). Capable of searching eight different databases simultaneously
Polyglot Use the Polyglot tool to translate search strings from PubMed across multiple databases. Access the tool's tutorial for more information (https://sr-accelerator.com/#/help/polyglot).
MEDLINE Transpose Use this tool to translate your MEDLINE (PubMed) search to MEDLINE (Ovid) format or vice versa.
Database Syntax Guide Guide to translating syntax for multiple databases. From Cochrane.

_____________________________________________________________

Take control of your search and turn off Pubmed's Automatic Term Mapping (ATM) ! It will not include all variant terminology and automatically explodes MeSH terms. Not using ATM allows for clearer documentation of the search method.

For more information on Automatic Term Mapping, watch the video below .

Hedges by Topic (in alphabetical order )

Prady, S. L., Uphoff, E. P., Power, M., & Golder, S. (2018). Development and validation of a search filter to identify equity-focused studies: Reducing the number needed to screen. BMC Medical Research Methodology, 18 (1), 106. https://doi.org/10.1186/s12874-018-0567-x
Health Risk Assessment by Vicky Tessier at the INSPQ
Effectiveness of Interventions
van der Mierden, S., Hooijmans, C. R., Tillema, A. H., Rehn, S., Bleich, A., & Leenaars, C. H. (2022). Laboratory animals search filter for different literature databases: PubMed, Embase, Web of Science and PsycINFO. Laboratory animals , 56 (3), 279–286. https://doi.org/10.1177/00236772211045485
Updated Press Checklist (2015) See page 41-42
IOM Standards for Systematic Reviews
PRESS Checklist

McGowan J, Sampson M, Salzwedel DM, Cogo E, Foerster V, Lefebvre C. PRESS Peer Review of Electronic Search Strategies: 2015 guideline statement . Journal of Clinical Epidemiology, 75 , 40-46.

Systematic Literature Review Worksheet

Use the Database Search Log to record your search terms, search strategy and databases searched.

Guidance on Reporting Systematic Reviews

Cochrane strongly encourages that review authors include a study flow diagram as recommended by the PRISMA statement.

PRISMA Flow Diagram
PRISMA Flow Diagram Generator
PRISMA Checklist

Other checklists include:

ARRIVE and DSPC for animal studies
MOOSE - meta-analysis of observational studies in epidemiology
STARLITE - general health policy and clinical practice
TIDier-PHP - population health and policy interventions

Examples of documented search methodologies:

Full search strategies for all database searches provided in the Appendices:

Bath, P. & Krishnan, K. (2014). Interventions for deliberately altering blood pressure in acute stroke . Cochrane Database of Systematic Reviews, 10.

A summary of sources searched and keywords used in the Sources section:

McIntyre, S, Taitz, D, Keogh, J, Goldsmith, S, Badawi, N & Blair, E. (2013). A systematic review of risk factors for cerebral palsy in children born at term in developed countries . Developmental Medicine & Child Neurology, 55( 6), 499-508.

ACRL Systematic Reviews & Related Methods Interest Group [email protected]
Cindy Schmidt's Blog: PubMed Search Strategies This blog has been created to share PubMed search strategies. Search strategies posted here are not perfect. They are posted in the hope that others will benefit from the work already put into their creation and/or will offer suggestions for improvements.
MedTerm Search Assist from the University of Pittsburgh By librarians for librarians - A database to share biomedical terminology and strategies for comprehensive searches.
MLA expert searching discussion list [email protected] - This discussion list often discusses subject strategies and sometimes search filters.
PRESS Forum This closed wiki-based forum is a place for librarians to request reviews of systematic review search strategies, and to review the searches of others.
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Last Updated: May 8, 2024 1:44 PM
URL: https://lib.guides.umd.edu/SR

Systematic Reviews

The Research Question
Inclusion and Exclusion Criteria
Original Studies
Translating
Deduplication
Project Management Tools
Useful Resources
What is not a systematic review?

Search Strings

Systematic review search strings can be incredibly complex. This is why it is fundamental to have an information specialist on the research team. For an example of a systematic review search strategy, please examine the document below to see additional information from M.D. Anderson Cancer Center Library.

Example Search String in 3 Databases
Preliminary Search
Exhaustive Search
Hand Search
Contact Experts

A preliminary search is about planning and developing your protocol . It helps the research team understand what the review would/should entail, and the preliminary search will also give an estimate for the time and funding commitment necessary for the investigation. Researchers should assume an exhaustive search will identify about 2-3 times more the number of citations than the preliminary search.

1. Searching for research trends

You need to see a sample of the research trends within the research area. You don’t know the general scope of the literature until you run a preliminary search. You must also sample these results for information for the background and objectives' section in the protocol.

A sampling of the preliminary results also helps you formulate the research question. The research question must be shaped by the pre-existing literature because enough pre-existing literature must exist in the first place to attempt to answer the research question.

2. Look to see if a systematic or scoping review already exists

Look to see if someone has already published a systematic/scoping review on your topic. This is again to analyze the research trends, but it is also important to not duplicate work that is already done.

3. Identifying preliminary MeSH/Subject Headings and keywords/keyphrases

You can identify the preliminary MeSH/subject headings, keywords, and key phrases you will need in your exhaustive search strategy. You will have more terms in your final search, but you must identify the basic subject headings and keywords you will need. This is the information that goes in your Search Methods section of your protocol. What goes in this Search Methods section of the protocol are the terms you found during your preliminary searching phase.

4. Getting test articles

Select 5-10 test articles from the preliminary search to use to test your future, exhaustive search strategy (i.e. the search to get your citations for your review). These 5-10 test articles should be articles that *should* make it to the end of review based on inclusion/exclusion criteria.
Researchers may have access to journal subscriptions. Being familiar with a journal and finding articles on the team's topic helps to see what research exists. It can help the information specialist find relevant subject headings and keywords for the search strategy. Additionally, the search strategy that is developed should be able to retrieve these articles that are known to directly address the team's research question.

5. Preparatory contacting of experts

One of t he goals of contacting experts is to identify unregistered studies with unpublished results. It is important to find experts on the research question because they will know what the current climate is on the research topic. Finally, the research team could benefit from this networking for later stages in the review.

The Exhaustive Search

This is the search designed by a librarian trained on how to design searches for systematic reviews. One goal of an exhaustive search is to identify all publications and as much grey literature as possible that meet study requirements. At least three databases should be utilized to conduct an exhaustive search. Another goal is to document and report the exhaustive search in such a way that it can be replicated for updates and reproduced by others after publication. See the Texas Medical Center Library's S.R. Database and Resources Libguide .

Study types and other considerations

There are many things to consider when searching for and identifying the literature relevant to the research question. Researchers should be familiar with the study types and their uses for systematic reviews.

Randomized Clinical Trials (RCTs): A study where there is an initial research question, and there are controls for population and the intervention to be studied. 'Randomized' refers to the population participants, where groups are divided into categories that either receive the studied intervention and those who receive the contemporary treatment or placebo.

Dissertations and unpublished research: The importance of searching for dissertations come into play when there is little research on a new or emerging topic. Additionally, within the published research there may already be problematic bias. Searching within these resources again helps reduce bias within the review.

Non-English studies: There may also be geographical bias in studies. It is important to search non-English studies to identify all the relevant literature for a topic.

Hand Search

Hand searching identifies grey literature like conference proceedings, abstracts for posters, and presented papers not indexed in online databases. Sources to hand search include: subject specific professional association websites; included studies' bibliographies; and topic review bibliographies. Hand searching can be done within research centers such as archives that house information resources out of circulation. It is important to document all sources searched by hand. Information regarding the number of hand searched resources used and where resources are located should be reported within the PRISMA Flow Diagram .

1. Clarification of the data

Some systematic reviews involve a meta-analysis. There may be questions regarding the data produced from the study. Contacting experts to clarify data findings helps develop better accuracy and transparency of the information that will be generated from the systematic review.

There are some systematic reviews, which require image analysis. Images that are used within published journals may not be easily synthesized or examined. The quality of the original image published in the journal article could make analysis difficult. Contacting the researchers for the raw data images will help the systematic review team better conduct image synthetization and analysis.

3. New developments

A systematic review can take 1-2 years. After the search strategy is developed the search has to be deduplicated. When a search is reran, some new articles may be retrieved. Being in contact with the experts helps the systematic review team know what other research is out there, so that information can be put into the review for the principle of transparency.

Caveats for searching

It is important to search three to five databases . The databases and how many you choose to search depends on the topic of the systematic review. Ultimately, be sure you consult with a librarian or information specialist before undertaking your searches for studies.

<< Previous: Inclusion and Exclusion Criteria
Next: Original Studies >>
Last Updated: Oct 12, 2023 12:30 PM
URL: https://libguides.sph.uth.tmc.edu/SystematicReviews

Systematic Reviews and Meta-Analyses: Where to Search

Get Started
Exploratory Search
Where to Search
How to Search
Grey Literature
What about errata and retractions?
Eligibility Screening
Critical Appraisal
Data Extraction
Synthesis & Discussion
Assess Certainty
Share & Archive

This page provides more information about where to search .

The short answer: Search anywhere that may contain information that can answer your research question(s)

Where to search

Registries & preprints
Online resources
Citation searching
What about Predatory Journals?

Because most research questions suited for a systematic review will be answerable with primary peer-reviewed empirical research , academic journal databases will likely be your team's primary resource.

Identifying Relevant Databases

A great place to start is your institutions' list of databases - VT's A-Z List of Databases - and subject guides - VT's Subject Guides . For a systematic review, it is important to search in several databases relevant to your research questions , which may mean searching in databases outside of your primary discipline.

Subject librarians can help you to find databases appropriate for your topic! Find VT subject librarian contact information in the accompanying Subject Guide . .

Searching Databases

The exact search 'string' you'll use in each database will depend on the database, because the syntax required by each database will vary. However, the search terms you use and any limitations (e.g., language, geographic location) should remain consistent. Before running your search in each database, it is best to develop a base search strategy, troubleshooting in one or two databases.

For more about designing a search string, go to the How to search tab.

Downloading Results from Databases

In a systematic review, you do not determine the relevance of references in the database itself. Instead, download all references yielded by your search into a citation manager . This process allows for more transparency as the exact yield (count and content) from the comprehensive search is documented and the process for determining relevance is systematic and, in theory, replicable.

Download Limits

Please note that the University Libraries and our vendors implement download limits that may be reached when attempting to perform a comprehensive search via EZProxy . We know these limitations can be frustrating, but they are here to protect services for all users. Learn more by visiting our Collections Management Policy Library Guide.

If you encounter problems with these limits, please contact [email protected]

Gusenbauer M, Haddaway NR. Which academic search systems are suitable for systematic reviews or meta-analyses? Evaluating retrieval qualities of Google Scholar, PubMed, and 26 other resources . Res Synth Methods. 2020 Mar;11(2):181-217. doi: 10.1002/jrsm.1378. Epub 2020 Jan 28. PMID: 31614060; PMCID: PMC7079055

UX Caucus Database Search Tips

Study Registries & Preprint Archives

For a comprehensive search, it's important to locate and include unpublished to the extent possible in order to reduce the risk of missing important emerging information and to avoid risk of publication bias .

Study registries contain unpublished research , which may (or may not) be considered a type of grey literature in your field. Research may be unpublished for several reasons - for example, the research is still in progress or not ready to publish. Sometimes research is unpublished for other reasons, such as negative or null results, or the study was not considered novel (e.g., replications).

Some health-based study (and clinical trial) registeres include:

clinicaltrials.gov from the US National Libraries of Medicine
International Clinical Trials Registry Platform (ICTP) from the World Health Organization
ISRCTN Registry from BCM Springer Nature
Australian Clinical Trials from the Australian Government

Preprints are studies that have not yet been peer-reviewed and/or published by a journal. Preprints exist to get research into the community more quickly; much of this material ends up going through the formal peer review and publishing process. Note: it is important to match preprints with their subsequent publication(s) and to not duplicate findings in your synthesis.

Some archives to explore include:

Online Resources

It is best practice to supplement primary searching (done in academic databases) by searching other online resources and web browsing. This kind of searching may result in additional primary research and/or grey literature.

Web search engines and specific websites

While general search engines like Google should never be the primary resource for your search, it is a great way to supplement the results of academic database searches. These searches may yield primary research and grey literature .

Companies like Google tailor search results to individual users, which increase the risk of introducing bias, but there are ways to reduce this risk. For example, log out of your account, use 'incognito' mode (or similar), and/or opt for a search engine that doesn't track your data like DuckDuckGo or StartPage .

In contrast to searches in academic databases, it is more often appropriate to apply artificial limits in web searches, as yields tend to be unmanageable. For example, a team may only review the first 200 records (or 20 pages) . Search strings themselves may also need to be refined to accommodate character limits in both general search engines and specific websites. Exactly how to search specific websites will vary. Note that you can also use general search engines to search within specific websites or even types of websites (e.g., government sites by specifying a .gov url).

Resources for web browsing

Google Scholar Search Tips
Bulk Downloading from Google Scholar
Google Syntax Tips (Sheridan College Library Guide)
Google Custom/Programmable Search ( instructions from WorldBank/IMF Library Guide )
Set Google Alerts
MillionShort ( can remove top hits to find what you're missing )
Haddaway NR, Collins AM, Coughlin D, Kirk S (2015) The Role of Google Scholar in Evidence Reviews and Its Applicability to Grey Literature Searching. PLoS ONE 10(9): e0138237. https://doi-org.ezproxy.lib.vt.edu/10.1371/journal.pone.0138237

Piasecki, J., Waligora, M., & Dranseika, V. (2018). Google Search as an Additional Source in Systematic Reviews. Science and engineering ethics , 24 (2), 809–810. https://doi.org/10.1007/s11948-017-0010-4

Citation Searching

Citation searching, also referred to as pearl growing, snowballing, and citation chasing , chaining , or tracking, describes two processes:

Backward citation chasing, where reviewers scan work cited by included references and other relevant reviews, and

Forward citation chasing, where reviewers search for references that cit e the references included in your review and other relevant reviews.

In a comprehensive search, we often find existing reviews (e.g., traditional reviews, scoping reviews, restricted/rapid reviews) on the same topic and/or other systematic reviews on similar topics . Though it is not appropriate to synthesize the reviews themselves in your review, be sure to use them in your citation search .

Citation searching applied to included references (references your team has already identified as relevant). As such, this step does not take place until after reviewing the full-Text of included references.

How to citation search?

Citation searching can be done manually (e.g., reviewing full text) and by using bibliographic databases that index both citations and standard bibliographic data. For example, Web of Science Core Collection provided by Clarivate Analytics, Scopus provided by Elsevier, and Google Scholar (for forward citation searching only).

There are also semi-automated tools available to support this stage, such as Citation Chaser and SpiderCite .

Personal Contacts

Contacting relevant authors and other stakeholders can occur during the:

Comprehensive searching phase to collect unpublished research or other grey literature, and

Eligibility screening , critical appraisal , and data extraction phases as follow-up when there is not enough information provided in an original publication to determine relevance, appraise quality, or extract data properly.

Also consider contacting groups, organizations, committees, listservs, etc.

Predatory Journals

"Predatory journals-also called fraudulent, deceptive, or pseudo-journals-are publications that claim to be legitimate scholarly journals but misrepresent their publishing practices. Some common forms of predatory publishing practices include falsely claiming to provide peer review, hiding information about article processing charges, misrepresenting members of the journal's editorial board, and other violations of copyright or scholarly ethics." ( Elmore & Wetson, 2020 )

For more about predatory journals, check out the GRAD 5124 topic 11.4 Issues in Academic Publishing .

Predatory Journals in Systematic Reviews

Given the description above, it's no surprise that whether or not to include and how to include publications from predatory publishers in systematic reviews and/or meta-analyses. However, the poor practices of a publisher does not necessarily mean the research published there was done poorly. There have been a few recommendations set forth over the years.

Poliani, et al. (2020) recommend to:

determine whether the journal or publisher is part of COPE, DOAJ, OASP, INASP Journals Online Platform, STM (global voice of scholarly publishing), and
critically appraise reports from uncertain journals or publishers using a tool like Think, Check, Submit

According to Munn, et al., (2021) , "Options for systematic reviewers could include excluding all studies from suspected predatory journals, applying additional strategies to forensically examine the results of studies published in suspected predatory journals, setting stringent search limits , and applying analytical techniques (such as subgroup or sensitivity analyses) to investigate the impact of suspected predatory journals in a synthesis."

And Rice, et al. (2021) suggest to include "(1) detail methods for addressing predatory journal articles a priori in a study protocol , (2) determine whether included studies are published in open access journals and if they are listed in the directory of open access journals, and (3) conduct a sensitivity analysis with predatory papers excluded from the synthesis."

Elmore SA, Weston EH. Predatory Journals: What They Are and How to Avoid Them . Toxicol Pathol. 2020 Jun;48(4):607-610. doi: 10.1177/0192623320920209. Epub 2020 Apr 22. PMID: 32319351; PMCID: PMC7237319.

John D, Polani Chandrasekar R, Lohmann J, Dazy A. Identifying predatory journals in systematic reviews. In: Advances in Evidence Synthesis: special issue Cochrane Database of Systematic Reviews 2020;(9 Suppl 1). https://doi.org/10.1002/14651858.CD202001

Munn Z, Barker T, Stern C, Pollock D, Ross-White A, Klugar M, Wiechula R, Aromataris E, Shamseer L. Should I include studies from "predatory" journals in a systematic review? Interim guidance for systematic reviewers. JBI Evid Synth. 2021 Jun 28;19(8):1915-1923. doi: 10.11124/JBIES-21-00138. PMID: 34171895.

Rice, D.B., Skidmore, B. & Cobey, K.D. Dealing with predatory journal articles captured in systematic reviews . Syst Rev 10, 175 (2021). https://doi-org.ezproxy.lib.vt.edu/10.1186/s13643-021-01733-2

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Next: How to Search >>
Last Updated: May 6, 2024 11:56 AM
URL: https://guides.lib.vt.edu/SRMA

Systematic Review

Systematic reviews

Being systematic

Search terms, choosing databases, finding additional resources.

Search techniques
Systematically search databases
Appraisal & synthesis
Reporting findings
Systematic review tools

Searching literature systematically is useful for all types of literature reviews!

However, if you are writing a systematic literature review the search needs to be particularly well planned and structured to ensure it is:

comprehensive
transparent

These help ensure bias is eliminated and the review is methodologically sound.

To achieve the above goals, you will need to:

create a search strategy and ensure it is reviewed by your research group
document each stage of your literature searching
report each stage of quality appraisal

Identify the key concepts in your research question

The first step in developing your search strategy is identifying the key concepts your research question covers.

A preliminary search is often done to understand the topic and to refine your research question.

Identify search terms

Use an iterative process to identify useful search terms for conducting your search.

Brainstorm keywords and phrases that can describe each concept you have identified in your research question.
Create a table to record these keywords
Select your keywords carefully
Check against inclusion/exclusion criteria
Repeated testing is required to create a robust search strategy for a systematic review
Run your search on your primary database and evaluate the first page of records to see how suitable your search is
Identify reasons for irrelevant results and adjust your keywords accordingly
Consider whether it would be useful to use broader or narrower terms for your concepts
Identify keywords in relevant results that you could add to your search to retrieve more relevant resources

Using a concept map or a mind map may help you clarify concepts and the relationships between or within concepts. Watch these YouTube videos for some ideas:

How to make a concept map (by Lucidchart)
Make sense of this mess world - mind maps (by Sheng Huang)

Example keywords table:

Research question: What is the relationship between adverse childhood experiences and depression in mothers during the perinatal period?

Revise your strategy/search terms until :

the results match your research question
you are confident you will find all the relevant literature on your topic

See Creating search strings for information on how to enter your search terms into databases.

Example search string (using Scopus's Advanced search option) for the terms in the above table:

(TITLE-ABS-KEY("advserse childhood experienc*" OR ACE OR "childhood trauma") AND TITLE-ABS-KEY("perinatal depress*" OR "postpartum depress*" OR "postnatal depress*" OR "maternal mental health" OR "maternal psychological distress") AND TITLE-ABS-KEY(mother* OR women*))

See Subject headings for information on including these database specific terms to your search terms.

Systematic reviewers usually use several databases to search for literature. This ensures that the searching is comprehensive and biases are minimised.

Use both subject-specific and multidisciplinary databases to find resources relevant to your research question:

Subject-specific databases: in-depth coverage of literature specific to a research field.
Multi-disciplinary databases: literature from many research fields - help you find resources from disciplines you may not have considered.

Check for databases in your subject area via the Databases tab > Find by subject on the library homepage .

Find the key databases that are often used for systematic reviews in this guide.

Test searches to determine database usefulness. You can consult your Liaison Librarians to finalise the list of databases for your review.

Recommendations:

For all systematic reviews we recommend using Scopus , a high-quality, multidisciplinary database:

Scopus is an abstract and citation database with links to full text on publisher websites or in other databases.
Scopus indexes a curated collection of high quality journals along with books and conference proceedings.
Research outputs are across a range of fields - science, technology, medicine, social science, arts and humanities.

For systematic reviews within the health/biomedical field, we recommend including Medline as one of the databases for your review:

MEDLINE (via Ebsco, via Ovid, via PubMed)

Medline is the National Library of Medicine’s (NLM) article citation database.
Medline is hosted individually on a variety of platforms (EBSCO, OVID) and comprises the majority of PubMed.
Articles in Medline are indexed using MeSH headings. See Subject headings for more information on MeSH.

Note: PubMed contains all of Medline and additional citations, e.g. books, manuscripts, citations that predate Medline.

To ensure your search is comprehensive you may need to search beyond academic databases when conducting a systematic review, particularly to find grey literature (literature not published commercially and outside traditional academic sources such as journals).

Google Scholar

Google Scholar contains academic resources across disciplines and sources types. These come from academic publishers, professional societies, online repositories, universities and web sites.

Use Google Scholar

as an additional tool to locate relevant publications not included in high-level academic databases
for finding grey literature such as postgraduate theses and conference proceedings

You can limit your search to the type of websites by using site:ac . nz; site:edu

Note that Google Scholar searches are not as replicable or transparent as academic database searches, and may find large numbers of results.

Other sources of grey literature

Grey literature checklist (health related grey literature)
OpenGrey
Public health Ontario guide to appraising grey literature
Institutional Repository for Information Sharing (IRIS)
Google search: use it for finding government reports, policies, theses, etc. You can limit your search to a particular type of websites by including site : govt.nz, site: . gov, site: . ac . nz, site: . edu, in your search

Watch our Finding grey literature video (3.49 mins) online.

<< Previous: Planning
Next: Search techniques >>
Last Updated: May 7, 2024 9:49 AM
URL: https://aut.ac.nz.libguides.com/systematic_reviews

UNC Libraries
HSL Academic Process
Systematic Reviews
Step 3: Conduct Literature Searches

Systematic Reviews: Step 3: Conduct Literature Searches

Created by health science librarians.

Step 1: Complete Pre-Review Tasks
Step 2: Develop a Protocol

About Step 3: Conduct Literature Searches

Partner with a librarian, systematic searching process, choose a few databases, search with controlled vocabulary and keywords, acknowledge outdated or offensive terminology, helpful tip - building your search, use nesting, boolean operators, and field tags, build your search, translate to other databases and other searching methods, document the search, updating your review.

Searching FAQs
Step 4: Manage Citations
Step 5: Screen Citations
Step 6: Assess Quality of Included Studies
Step 7: Extract Data from Included Studies
Step 8: Write the Review

Check our FAQ's

Email us

Call (919) 962-0800

Make an appointment with a librarian

Request a systematic or scoping review consultation

Search the FAQs

In Step 3, you will design a search strategy to find all of the articles related to your research question. You will:

Define the main concepts of your topic
Choose which databases you want to search
List terms to describe each concept
Add terms from controlled vocabulary like MeSH
Use field tags to tell the database where to search for terms
Combine terms and concepts with Boolean operators AND and OR
Translate your search strategy to match the format standards for each database
Save a copy of your search strategy and details about your search

There are many factors to think about when building a strong search strategy for systematic reviews. Librarians are available to provide support with this step of the process.

Click an item below to see how it applies to Step 3: Conduct Literature Searches.

Reporting your review with PRISMA

For PRISMA, there are specific items you will want to report from your search. For this step, review the PRISMA-S checklist.

PRISMA-S for Searching
Specify all databases, registers, websites, organizations, reference lists, and other sources searched or consulted to identify studies. Specify the date when each source was last searched or consulted. Present the full search strategies for all databases, registers and websites, including any filters and limits used.
For information on how to document database searches and other search methods on your PRISMA flow diagram, visit our FAQs "How do I document database searches on my PRISMA flow diagram?" and "How do I document a grey literature search for my PRISMA flow diagram?"

Managing your review with Covidence

For this step of the review, in Covidence you can:

Document searches in Covidence review settings so all team members can view
Add keywords from your search to be highlighted in green or red while your team screens articles in your review settings

How a librarian can help with Step 3

When designing and conducting literature searches, a librarian can advise you on :

How to create a search strategy with Boolean operators, database-specific syntax, subject headings, and appropriate keywords
How to apply previously published systematic review search strategies to your current search
How to test your search strategy's performance
How to translate a search strategy from one database's preferred structure to another

The goal of a systematic retrieve is to find all results that are relevant to your topic. Because systematic review searches can be quite extensive and retrieve large numbers of results, an important aspect of systematic searching is limiting the number of irrelevant results that need to be screened. Librarians are experts trained in literature searching and systematic review methodology. Ask us a question or partner with a librarian to save time and improve the quality of your review. Our comparison chart detailing two tiers of partnership provides more information on how librarians can collaborate with and contribute to systematic review teams.

Decorative Image: Magnifying glass looking at city lights

Search Process

Use controlled vocabulary, if applicable
Include synonyms/keyword terms
Choose databases, websites, and/or registries to search
Translate to other databases
Search using other methods (e.g. hand searching)
Validate and peer review the search

Databases can be multidisciplinary or subject specific. Choose the best databases for your research question. Databases index various journals, so in order to be comprehensive, it is important to search multiple databases when conducting a systematic review. Consider searching databases with more diverse or global coverage (i.e., Global Index Medicus) when appropriate. A list of frequently used databases is provided below. You can access UNC Libraries' full listing of databases on the HSL website (arranged alphabetically or by subject ).

Generally speaking, when literature searching, you are not searching the full-text article. Instead, you are searching certain citation data fields, like title, abstract, keyword, controlled vocabulary terms, and more. When developing a literature search, a good place to start is to identify searchable concepts of the research question, and then expand by adding other terms to describe those concepts. Read below for more information and examples on how to develop a literature search, as well as find tips and tricks for developing more comprehensive searches.

Identify search concepts and terms for each

Start by identifying the main concepts of your research question. If unsure, try using a question framework to help identify the main searchable concepts. PICO is one example of a question framework and is used specifically for clinical questions. If your research question doesn't fit into the PICO model well, view other examples of question frameworks and try another!

View our example in PICO format

Question: for patients 65 years and older, does an influenza vaccine reduce the future risk of pneumonia, controlled vocabulary.

Controlled vocabulary is a set of terminology assigned to citations to describe the content of each reference. Searching with controlled vocabulary can improve the relevancy of search results. Many databases assign controlled vocabulary terms to citations, but their naming schema is often specific to each database. For example, the controlled vocabulary system searchable via PubMed is MeSH, or Medical Subject Headings. More information on searching MeSH can be found on the HSL PubMed Ten Tips Legacy Guide .

Note: Controlled vocabulary may be outdated, and some databases allow users to submit requests to update terminology.

View Controlled Vocabulary for our example PICO

As mentioned above, databases with controlled vocabulary often use their own unique system. A listing of controlled vocabulary systems by database is shown below.

Keyword Terms

Not all citations are indexed with controlled vocabulary terms, however, so it is important to combine controlled vocabulary searches with keyword, or text word, searches.

Authors often write about the same topic in varied ways and it is important to add these terms to your search in order to capture most of the literature. For example, consider these elements when developing a list of keyword terms for each concept:

American versus British spelling
hyphenated terms
quality of life
satisfaction
vaccination
influenza vaccination

There are several resources to consider when searching for synonyms. Scan the results of preliminary searches to identify additional terms. Look for synonyms, word variations, and other possibilities in Wikipedia, other encyclopedias or dictionaries, and databases. For example, PubChem lists additional drug names and chemical compounds.

Display Controlled Vocabulary and Keywords for our example PICO

Combining controlled vocabulary and text words in PubMed would look like this:

"Influenza Vaccines"[Mesh] OR "influenza vaccine" OR "influenza vaccines" OR "flu vaccine" OR "flu vaccines" OR "flu shot" OR "flu shots" OR "influenza virus vaccine" OR "influenza virus vaccines"

Social and cultural norms have been rapidly changing around the world. This has led to changes in the vocabulary used, such as when describing people or populations. Library and research terminology changes more slowly, and therefore can be considered outdated, unacceptable, or overly clinical for use in conversation or writing.

For our example with people 65 years and older, APA Style Guidelines recommend that researchers use terms like “older adults” and “older persons” and forgo terms like “senior citizens” and “elderly” that connote stereotypes. While these are current recommendations, researchers will recognize that terms like “elderly” have previously been used in the literature. Therefore, removing these terms from the search strategy may result in missed relevant articles.

Research teams need to discuss current and outdated terminology and decide which terms to include in the search to be as comprehensive as possible. The research team or a librarian can search for currently preferred terms in glossaries, dictionaries, published guidelines, and governmental or organizational websites. The University of Michigan Library provides suggested wording to use in the methods section when antiquated, non-standard, exclusionary, or potentially offensive terms are included in the search.

Check the methods sections or supplementary materials of published systematic reviews for search strategies to see what terminology they used. This can help inform your search strategy by using MeSH terms or keywords you may not have thought of. However, be aware that search strategies will differ in their comprehensiveness.

You can also run a preliminary search for your topic, sort the results by Relevance or Best Match, and skim through titles and abstracts to identify terminology from relevant articles that you should include in your search strategy.

Nesting is a term that describes organizing search terms inside parentheses. This is important because, just like their function in math, commands inside a set of parentheses occur first. Parentheses let the database know in which order terms should be combined.

Always combine terms for a single concept inside a parentheses set. For example:

( "Influenza Vaccines"[Mesh] OR "influenza vaccine" OR "influenza vaccines" OR "flu vaccine" OR "flu vaccines" OR "flu shot" OR "flu shots" OR "influenza virus vaccine" OR "influenza virus vaccines" )

Additionally, you may nest a subset of terms for a concept inside a larger parentheses set, as seen below. Pay careful attention to the number of parenthesis sets and ensure they are matched, meaning for every open parentheses you also have a closed one.

Boolean operators

Boolean operators are used to combine terms in literature searches. Searches are typically organized using the Boolean operators OR or AND. OR is used to combine search terms for the same concept (i.e., influenza vaccine). AND is used to combine different concepts (i.e., influenza vaccine AND older adults AND pneumonia). An example of how Boolean operators can affect search retrieval is shown below. Using AND to combine the three concepts will only retrieve results where all are present. Using OR to combine the concepts will retrieve results that use all separately or together. It is important to note that, generally speaking, when you are performing a literature search you are only searching the title, abstract, keywords and other citation data. You are not searching the full-text of the articles.

The last major element to consider when building systematic literature searches are field tags. Field tags tell the database exactly where to search. For example, you can use a field tag to tell a database to search for a term in just the title, the title and abstract, and more. Just like with controlled vocabulary, field tag commands are different for every database.

If you do not manually apply field tags to your search, most databases will automatically search in a set of citation data points. Databases may also overwrite your search with algorithms if you do not apply field tags. For systematic review searching, best practice is to apply field tags to each term for reproducibility.

For example:

("Influenza Vaccines"[Mesh] OR "influenza vaccine"[tw] OR "influenza vaccines"[tw] OR "flu vaccine"[tw] OR "flu vaccines"[tw] OR "flu shot"[tw] OR "flu shots"[tw] OR "influenza virus vaccine"[tw] OR "influenza virus vaccines"[tw] OR ((flu[tw] OR influenza[tw]) AND (vaccine[tw] OR vaccines[tw] OR vaccination[tw] OR immunization[tw])))

View field tags for several health databases

For more information about how to use a variety of databases, check out our guides on searching.

Searching PubMed guide Guide to searching Medline via the PubMed database
Searching Embase guide Guide to searching Embase via embase.com
Searching Scopus guide Guide to searching Scopus via scopus.com
Searching EBSCO Databases guide Guide to searching CINAHL, PsycInfo, Global Health, & other databases via EBSCO

Combining search elements together

Organizational structure of literature searches is very important. Specifically, how terms are grouped (or nested) and combined with Boolean operators will drastically impact search results. These commands tell databases exactly how to combine terms together, and if done incorrectly or inefficiently, search results returned may be too broad or irrelevant.

For example, in PubMed:

(influenza OR flu) AND vaccine is a properly combined search and it produces around 50,000 results.

influenza OR flu AND vaccine is not properly combined. Databases may read it as everything about influenza OR everything about (flu AND vaccine), which would produce more results than needed.

We recommend one or more of the following:

put all your synonyms together inside a set of parentheses, then put AND between the closing parenthesis of one set and the opening parenthesis of the next set
use a separate search box for each set of synonyms
run each set of synonyms as a separate search, and then combine all your searches
ask a librarian if your search produces too many or too few results

View the proper way to combine MeSH terms and Keywords for our example PICO

Question: for patients 65 years and older, does an influenza vaccine reduce the future risk of pneumonia , translating search strategies to other databases.

Databases often use their own set of terminology and syntax. When searching multiple databases, you need to adjust the search slightly to retrieve comparable results. Our sections on Controlled Vocabulary and Field Tags have information on how to build searches in different databases. Resources to help with this process are listed below.

Polyglot search A tool to translate a PubMed or Ovid search to other databases
Search Translation Resources (Cornell) A listing of resources for search translation from Cornell University
Advanced Searching Techniques (King's College London) A collection of advanced searching techniques from King's College London

Other searching methods

Hand searching.

Literature searches can be supplemented by hand searching. One of the most popular ways this is done with systematic reviews is by searching the reference list and citing articles of studies included in the review. Another method is manually browsing key journals in your field to make sure no relevant articles were missed. Other sources that may be considered for hand searching include: clinical trial registries, white papers and other reports, pharmaceutical or other corporate reports, conference proceedings, theses and dissertations, or professional association guidelines.

Searching grey literature

Grey literature typically refers to literature not published in a traditional manner and often not retrievable through large databases and other popular resources. Grey literature should be searched for inclusion in systematic reviews in order to reduce bias and increase thoroughness. There are several databases specific to grey literature that can be searched.

Open Grey Grey literature for Europe
OAIster A union catalog of millions of records representing open access resources from collections worldwide
Grey Matters: a practical tool for searching health-related grey literature (CADTH) From CADTH, the Canadian Agency for Drugs and Technologies in Health, Grey Matters is a practical tool for searching health-related grey literature. The MS Word document covers a grey literature checklist, including national and international health technology assessment (HTA) web sites, drug and device regulatory agencies, clinical trial registries, health economics resources, Canadian health prevalence or incidence databases, and drug formulary web sites.
Duke Medical Center Library: Searching for Grey Literature A good online compilation of resources by the Duke Medical Center Library.

Systematic review quality is highly dependent on the literature search(es) used to identify studies. To follow best practices for reporting search strategies, as well as increase reproducibility and transparency, document various elements of the literature search for your review. To make this process more clear, a statement and checklist for reporting literature searches has been developed and and can be found below.

PRISMA-S: Reporting Literature Searches in Systematic Reviews
Section 4.5 Cochrane Handbook - Documenting and reporting the search process

At a minimum, document and report certain elements, such as databases searched, including name (i.e., Scopus) and platform (i.e. Elsevier), websites, registries, and grey literature searched. In addition, this also may include citation searching and reaching out to experts in the field. Search strategies used in each database or source should be documented, along with any filters or limits, and dates searched. If a search has been updated or was built upon previous work, that should be noted as well. It is also helpful to document which search terms have been tested and decisions made for term inclusion or exclusion by the team. Last, any peer review process should be stated as well as the total number of records identified from each source and how deduplication was handled.

If you have a librarian on your team who is creating and running the searches, they will handle the search documentation.

You can document search strategies in word processing software you are familiar with like Microsoft Word or Excel, or Google Docs or Sheets. A template, and separate example file, is provided below for convenience.

Search Strategy Documentation Template
Search Strategy Documentation Example

*Some databases like PubMed are being continually updated with new technology and algorithms. This means that searches may retrieve different results than when originally run, even with the same filters, date limits, etc.

When you decide to update a systematic review search, there are two ways of identifying new articles:

1. rerun the original search strategy without any changes. .

Rerun the original search strategy without making any changes. Import the results into your citation manager, and remove all articles duplicated from the original set of search results.

2. Rerun the original search strategy and add an entry date filter.

Rerun the original search strategy and add a date filter for when the article was added to the database ( not the publication date). An entry date filter will find any articles added to the results since you last ran the search, unlike a publication date filter, which would only find more recent articles.

Some examples of entry date filters for articles entered since December 31, 2021 are:

PubMed: AND ("2021/12/31"[EDAT] : "3000"[EDAT])
Embase: AND [31-12-2021]/sd
CINAHL: AND EM 20211231-20231231
PsycInfo: AND RD 20211231-20231231
Scopus: AND LOAD-DATE AFT 20211231

Your PRISMA flow diagram

For more information about updating the PRISMA flow diagram for your systematic review, see the information on filling out a PRISMA flow diagram for review updates on the Step 8: Write the Review page of the guide.

<< Previous: Step 2: Develop a Protocol
Next: Step 4: Manage Citations >>
Last Updated: May 10, 2024 5:39 PM
URL: https://guides.lib.unc.edu/systematic-reviews

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Doing a systematic review

Step 1: creating a protocol (PICO and other frameworks)
Step 2: choosing where to search

Getting your search right

Widening your search: truncation and wildcards, combining your terms: search operators, being more specific: phrase and proximity searching, using methodological search filters, adapting your search for different databases, creating a comprehensive search on pubmed (using field tags).

Step 4: running & recording your search
Step 5: managing your search results
Step 6: screening & evaluating
Step 7: synthesis and writing it up (including PRISMA flow diagrams)

Test your strategy!

Search the database for each of the test records and make a note of the unique record number for each one - in Medline this is in the UI field.
Run your search strategy.
Run a search for all the record numbers for your test set using 'OR' in between each one.
Lastly combine the result of your search strategy with the test set using 'OR'.
If the number of records retrieved stays the same then the strategy has identified all the records. If it doesn't, combine the result of your search strategy with the test set, this time using 'NOT'. This will identify the records in your test set which are not being retrieved. Work out why these weren't retrieved and adjust your search strategy accordingly.

abbreviations
related terms
UK/US spellings
singular/plural forms of words
thesaurus terms (where available)

Your search is likely to be complex and involve multiple steps. Look at the appendices of existing reviews for an idea of what's involved in creating a comprehensive search.

You will need to adapt your strategy for each database depending on the searching options available on each one.

The techniques described below will help ensure you cover everything. Contact your Academic Liaison Librarian if you would like guidance on constructing your search.

Contact your Academic Liaison Librarian
Watch our video introductions to doing a systematic review Watch video 2 in our series of videos on doing a systematic review which includes brief guidance on developing a search strategy.

Although databases are developing to automatically search for variant spellings, they might just search for the exact letters you type in. To ensure you don't miss something relevant use wildcard and truncation symbols to include spelling variations to widen your search.

A truncation symbol (*) retrieves any number of letters - useful to find different word endings based on the root of a word africa* will find africa, african, africans, africaans agricultur* will find agriculture, agricultural, agriculturalist

A wildcard symbol (?) replaces a single letter. It's useful for retrieving alternate spelling spellings (i.e. British vs. American English) and simple plurals wom?n will find woman or women behavio?r will find behaviour or behavior

Hint: Not all databases use the ? and * symbols, so check the online help screens before you start.

Watch our video on literature searching tips and tricks

Jump to 01:45 for truncation and 05:46 for wildcards.

If you are unable to view this video on YouTube it is also available on YuJa - view the Literature searching tips and tricks video on YuJa (University username and password required)

Introduction

Search operators (also called Boolean operators) allow you to include multiple words and concepts in your searches. This means you can search for all of your terms at once rather than carrying out multiple searches for each concept.

There are three main operators:

OR - for combining alternative words for your concepts and widening your results e.g. women OR gender
AND - for combining your concepts giving more specific results e.g. women AND africa
NOT - to exclude specific terms from your search - use this with caution as you might exclude relevant results accidentally!

This video covers a variety of techniques for creating a comprehensive search including using 'AND' and 'OR' to build a search statement.

women OR female

Using OR will bring you back records containing either of your search terms. It will return items that include both terms, but will also return items that contain only one of the terms.

This will give you a broader range of results.

OR can be used to link together synonyms. These are then placed in brackets to show that they are all the same concept.

(cat OR kitten OR feline)
(women OR female)

women AND Africa

Using AND will find items that contain both of your search terms, giving you a more specific set of results.

If you're getting too many results, using AND can be a good way to narrow your search.

women NOT Africa

Using NOT will find articles containing a particular term, but will exclude articles containing your second term.

Use this with caution - by excluding results you might miss out on key resources.

Phrase searching
Proximity searching

Sometimes your search may contain common words (i.e. development, communication) which will retrieve too many irrelevant records, even when using an AND search. On many databases, including Google, to look for a specific phrase, use inverted commas:

"agricultural development"
"foot and mouth"

Your search will only bring back items containing these exact phrases.

Some databases automatically perform a phrase search if you do not use any search operators. For example, "agriculture africa" is not a phrase used in English so you may not find any items on the subject. Use AND in between your search words to avoid this.

On Scopus to search for an exact phrase use { } e.g. {agricultural development}. Using quotes on Scopus will find your words in the same field (e.g. title) but not necessarily next to one another.

Some databases use proximity operators, which are a more advanced search function. You can use these to tell the database how close one word must be to another and, in some cases, in what order. This makes a search more specific and excludes irrelevant records.

For instance, if you were searching for references about women in Africa, you might retrieve irrelevant records for items about women published in Africa. Performing a proximity search will only retrieve the two words in the same sentence, making your search more accurate.

Each database has its own way of proximity searching, so it's important to check the online help before you start . Here are some examples of the variety of possible searches:

Web of Science : women same Africa - retrieves records where the words 'women' and 'Africa' appear in the same sentence
JSTOR : agricultural development ~5 - retrieves records where the words 'agricultural' and 'development' are within five words of one another
Scopus : agricultural W/2 development - retrieves records where the word 'agricultural' is within two words of the word 'development'.

Methodological search filters are search terms or strategies that identify a topic or aspect. They are predefined, tried and tested filters which can be applied to a search.

Study types: 'systematic reviews', 'RCT' (randomised control trials)

Age groups: 'children', 'elderly'

They are available to select via the results filters displayed alongside your results. For instance, on PubMed after running your results it is possible to limit by 'Ages' which gives predefined groupings such as 'Infant: birth-23 months'.

Each database is unique and has its own features and tools. If you are using truncation, wildcards and phrase searching you might need to adapt your search to ensure it works correctly on each database. For instance Web of Science uses quotation marks around phrases whereas Scopus uses these brackets { }. Filtering options will also vary.

This is an example of a search and how it would be adapted for three databases (Web of Science, Scopus and PubMed)

Example of adapting a search for several databases

Look at the help screens on the database you are using to work out the best strategy. Keep a record of the searches you run on each database to help you develop your search and to include in your write up. If you are doing a systematic review for publication your strategies need to be clearly and accurately recorded so that someone else could reproduce them.

Your Academic Liaison Librarian can also help you adjust your search.

Most health-related systematic reviews will involve a search on PubMed. But do you know how to create the most effective search strategy to take advantage of the Medical Subject Headings (MeSH)? This video created by John Hopkins University explains all the steps involved in ensuring your search is as comprehensive as possible.

<< Previous: Step 2: choosing where to search
Next: Step 4: running & recording your search >>
Last Updated: Apr 23, 2024 2:19 PM
URL: https://libguides.reading.ac.uk/systematic-review

Systematic Reviews

The Research Question
Basic Service
Full Service
Inclusion and Exclusion Criteria
Translating
Deduplication
Screening & Selection
Useful Resources
Other Review Types

Search Strings

Systematic review search strings can be incredibly complex. This is why it is fundamental to consult an information specialist (librarian). For an example of a systematic review search strategy, please examine the document from M.D. Anderson Cancer Center Library.

Example Search String in 3 Databases
Preliminary Search
Exhaustive Search
Hand Search
Contact Experts

1. Searching for research trends

A sampling of the preliminary results also helps you formulate The Research Question . The research question must be shaped by the pre-existing literature because enough pre-existing literature must exist in the first place to attempt to answer the research question.

2. Look to see if a systematic or scoping review already exists

Look to see if someone has already published a systematic/scoping review on your topic. This is again to analyze the research trends, but it is also important to not duplicate work that is already done.

3. Determine if a Systematic Review is Warranted

After you have done a preliminary search to determine research trends and looked to see if a a systematic or scoping review already exists on the topic, you must determine whether a systematic review is warranted. You may also determine that another review type is better for the research topic/question.
The difference between a systematic review and a literature review
Please see our page on Other Review Types for readings on how to choose between different reviews

4. Identifying preliminary MeSH/Subject Headings and keywords/keyphrases

You can identify the preliminary MeSH/subject headings, keywords, and key phrases you will need. You will have more terms in your final search, but you must identify the basic subject headings and keywords you will need. This is the information that goes in your Search Methods section of your protocol . What goes in this Search Methods section of the protocol are the terms you found during your preliminary searching phase.

For those who have been accepted for the Full Service , in the protocols you submit with your application; we ask that you identify the basic keywords for the search in the protocol. What is most helpful is if you provide the search terms you used to access relevant articles on the topic in the protocol. If acronyms are listed, please spell out and define.

5. Getting test articles

Select 5-10 test articles from the preliminary search to use to test your future, exhaustive search strategy (i.e. the search to get your citations for your review). These 5-10 test articles should be articles that *should* make it to the end of review based on inclusion/exclusion criteria.
Researchers may have access to journal subscriptions. Being familiar with a journal and finding articles on the team's topic helps to see what research exists. It can help the information specialist find relevant subject headings and keywords for the search strategy. Additionally, the search strategy that is developed should be able to retrieve these articles that are known to directly address the team's research question.

6. Preparatory contacting of experts

One of t he goals of contacting experts is to identify unregistered studies with unpublished results. It is important to find experts on the research question because they will know what the current climate is on the research topic. Finally, the research team could benefit from this networking for later stages in the review.

The Exhaustive Search

For those utilizing the Basic Service , we recommend the following resources to assist you with developing the exhaustive search to translate to the other predefined databases and t o get the citations .

For advanced search assistance check out the more advanced resources below:

The TMC Library Databases LibGuide : this is for those who want to learn how to translate a research question into a search strategy, which is necessary for systematic/scoping reviews
The TMC Library YouTube channel for all class recordings and tutorials
Searching 101 Database Cheat Sheet -- this resource was developed by the University of Michigan Library
Technical Supplement to Chapter 4: Searching for and selecting studies from Cochrane. Read Chapter Four before utilizing this resource.
Controlled vocabulary and text words from Cochrane Library
Search Smart There are dozens of academic databases, each offering unique coverages and features. To identify the ones most suitable for you, researchers can use the tool Search Smart to identify the databases you should use. This tool does NOT search databases.

If your application has been approved for the Full Service , the liaison librarian will develop the exhaustive search strategy. However, researchers are encouraged to check out the searching resources for other projects they may have.

Hand Search

1. Clarification of the data

3. New developments

Additional Search Tools

Search Strategies Concept Mapping Worksheet Use this worksheet to help you conceptualize your search, and organize your subject headings and keywords.
Search Strategies Concept Mapping Worksheet WITH ACUPUNCTURE QUESTION EXAMPLE Use this example PICO question to understand how to utilize the Search Strategies Concept Mapping Worksheet
Search Strategies Checklist This checklist is helpful for those newer to database searching. It is to assist with conceptualizing the search and organizing both subject headings and keywords. It assists with keeping your search organized.
Search 101 This cheat sheet was developed by Michigan State Library and has the syntax commands, codes, and subject headings lists of Health Sciences databases. This cheat sheet helps you translate your research concepts into search strategies. This is for advanced level searching for systematic and scoping review searches.

Searching for Clinical Trials

Cochrane advocates the use of the Cochrane Central Register of Controlled Trials (CENTRAL) . However, there are additional resources for locating randomized controlled trials. Take a look at other clinical trial databases to determine if there might be additional data that could affect the results of your systematic review.

Finding Unpublished Research Results in ClinicalTrials.gov
Released in 2000. Non-clinical studies are not required by law to be registered.
This is a meta-site; multiple national registries meet the standards established by the WHO ICTRP (including ClinicalTrials.gov).
<< Previous: Inclusion and Exclusion Criteria
Next: Translating >>
Last Updated: May 9, 2024 3:13 PM
URL: https://libguides.library.tmc.edu/Systematic_Reviews

Searching for Systematic Reviews & Evidence Synthesis: Advanced search techniques

Define your search question
Searching Databases
Drawing up your search strategy
Advanced search techniques
Using Filters
Grey Literature
Recording your search strategy and results
Managing References & Software Tools
Further information
Library Workshops, Drop ins and 1-2-1s
AI tools in evidence synthesis

Further help

Search operators in bibliographic databases Resource produced by NHS Shrewsbury & Telford Health Library providing guidance on using search operators in bibliographic databases.
Ovid Medline Database Guide - Advanced Searching Find out more about advanced search techniques on Ovid Medline (many applicable to other databases on the Ovid platform) including proximity searching, truncation and wildcards.

Most platforms and databases will provide guidance on advanced search techniques available. Visit the help/training section linked from the database or search online for the name of the database and the technique you wish to apply to locate guidance if it isn't listed on this page..

The asterisk * [Shift and 8 on a standard UK keyboard] is used by many databases - Scopus, Web of Science, all databases on the Ovid platform (Medline, Embase, PyscInfo etc), on the EBSCO platform (ERIC, CINAHL etc), on the NHS HDAS databases and the PROQUEST platform as a truncation command. You may also see $ used as a truncation symbol in databases on the Ovid platform but please note that $ is used as a different command in other databases.

Truncation instructs the database that when you are searching for a free-text keyword search that it should search for the root of the word you have typed in and then retrieve any alternate endings.

This is excellent for searching for plurals without having to type out both the singular and plural in your search, but will find also find any other alternative endings (some of which may not be relevant to your topic).

A keyword search for dentist* would retrieve any article which has the word dentist or dentists or dentistry somewhere in the title, abstract or other field. A keyword search for therap * would retrieve any articles where the word therapy or therapies appeared, but would also retrieve articles which included the word therapeutic (likely to be relevant) and also therapist(s) (perhaps less likely to be relevant if you were initially wanting to search for therapies).

In Web of Science the asterisk (*) represents any group of characters, including no character and can also be used within a word, e.g. s*food matches seafood and soyfood.

In those databases which use Subject Headings it is recommended that you search initially for your term in full without using truncation because if truncation is used then the database may fail to suggest appropriate subject headings even if one or more exist. Once you have located a relevant subject heading or headings for the concept then you can start to type in your keywords for that concept using truncation. If you receive an error message in Ovid that the search cannot be mapped to a subject heading (sometimes happens when using truncation) then simply untick the map box to subject heading before repeating the search. Remember to re-tick the box when you come to search for a new concept and you wish to see what subject headings are available.

PubMed Truncation: truncation, or finding all terms that begin with a given string of text, is generally not a recommended search technique for PubMed as truncation bypasses Automatic Term Mapping [to Subject Headings] and automatic explosion.

Floating subheadings

Subheadings are used to further describe a particular aspect of a subject heading in databases such as Medline, Embase and Cinahl.

An example might be (for Medline) 'thromboembolism/prevention and control' or the two-letter subheading abbreviation -- thromboembolism/pc. 'T h ro mboembolism ' is the subject heading and 'prevention and control' one of its subheadings (this will retrieve a subset of the results which have been tagged with the thromboembolism subject heading, limiting the results to only those articles discussing the prevention and control aspect).

However, it is possible in these databases to search for the subheading independent of any subject heading. This allows you to retrieve all articles which have been tagged with a particular subheading but without having to specify what subject headings it is attached to. A list of subheadings and abbreviations is available.

This can be very useful as seen in the example below where the search aims to retrieve any article in Medline tagged with the floa ting subheadings of Adverse Effects (ae), Complications (co) or Drug Effects (de) [search line 43] . In the Ovid databases to search using floating subheadings you can type the two letter subheading abbreviation followed by . fs. Keyword searches for safety, side effects, toxicity, adverse effects, etc were also undertaken in the search strategy [search lines 44-45] and the results brought together using OR [search line 46] before being combined with other elements of the search, e.g. the specific patient population and drug intervention which was being reviewed [for the full search strategy see the Appendix of the Cochrane Review linked below].

43. (ae or co or de).fs. 44. (safe or safety or (side adj1 effect*) or (undesirable adj1 effect*) or (treatment adj1 emergent) or tolerability or tolerance or tolerate or toxicity or toxic or adrs or adr or harm or harms or harmful or complication* or risk or risks or (unintended adj1 event*) or (unintended adj1 effect*)).ti,ab. 45. (adverse adj2 (effect or effects or reaction or reactions or event or events or outcome or outcomes)).ti,ab. 46. 43 or 44 or 45

Extract of Medline (Ovid) search strategy from: Storebø, O., Ramstad, E., Krogh, H., Nilausen, T., Skoog, M., Holmskov, M., Rosendal, S., Groth, C., Magnusson, F.L., Moreira-Maia, C.R., Gillies, D., Buch Rasmussen, K., Gauci, D., Zwi, M., Kirubakaran, R., Forsbøl, B., Simonsen, E., Gluud, C. (2015), 'Methylphenidate for children and adolescents with attention deficit hyperactivity disorder (ADHD)', Cochrane Database of Systematic Reviews , Issue 11. Art. No.: CD009885. DOI: 10.1002/14651858.CD009885.pub2

PRESS: Peer Review of Electronic Search Strategies

Performing a high quality electronic search of information resources ensures the accuracy and completeness of the evidence used in your review. However, errors have been found in search strategies of systematic reviews (even Cochrane ones!). PRESS EBC is an evidence-based checklist that has been developed to guide and inform the peer review of search strategies for database searching and can also be used to check your own search strategy.

PRESS 2015 Guideline Evidence-Based Checklist Structured tool for peer-reviewing systematic reviews.
PRESS Guideline — Search Submission & Peer Review Assessment Form to be filled in by searcher and reviewer undertaking the peer review assessment of the systematic review.

Yale MeSH Analyzer

The Yale MeSH Analyzer allows you to enter PMIDs* for different articles (up to 20 at a time) and generates a MeSH analysis grid presenting the ways these articles are indexed in the MEDLINE database (i.e. which subject headings have been assigned to each article) in an easy-to-scan tabular format.

This can provide you with a means to generate useful MeSH (Medline Subject Headings) from articles on your topic which you know are relevant. You can also use it to help identify the problems in your search strategy as you can easily scan the grid and identify appropriate MesH terms, term variants, indexing consistency, and the reasons why some articles are retrieved and others are not. This inevitably leads to fresh iterations of the search strategy to include missing important terms.

*PMIDs are a unique identifying number which are assigned to each article in the Medline database (appearing in the records of articles in both PubMed and Medline on OvidSP).

Yale MeSH Analyzer more... less... When conducting a comprehensive search, it is critical to design a strategy that retrieves all potentially relevant articles. Experienced searchers know the power of using controlled vocabularies but also the frustration of not being able to pinpoint articles known to be relevant but missing from the initial retrieval set. Librarians have long analyzed Medical Subject Headings to design and refine searches. A MeSH analysis grid can help identify the problems in your search strategy by presenting the ways articles are indexed in the MEDLINE database in an easy-to-scan tabular format. Typically, each column in the grid represents an article, with identifying information of the article at the top of the column, such as the PMID, the author, and the year of publication. The MeSH terms are sorted and grouped alphabetically for ease of scanning. Librarians can then easily scan the grid and identify appropriate MesH terms, term variants, indexing consistency, and the reasons why some articles are retrieved and others are not. This inevitably leads to fresh iterations of the search strategy to include missing important terms. In addition to MeSH terms, author-assigned keywords, article titles, and abstracts can be included in the analysis grid.

Proximity Searching

Proximity or adjacency searching using keywords allows you to search for two words or phrases that appear within a set number of words of each other (in any order). This is less precise than a phrase search (see the box on this page) but ensures it is more likely that the words/phrases will be related than a simple AND search. Different databases require you to type in different operators/commands in order to undertake a proximity search. Check the help pages for the database platform you are searching if the commands are not listed below.

OvidSP platform databases and e.g. Medline, Embase, PsycInfo

The ADJ operators finds two terms next to each other in the specified order. The ADJ1 operators finds two terms next to each other in any order. The ADJ2 operator finds terms in any order and with one word (or none) between them. The ADJ3 operator finds terms in any order with two words (or fewer) between them and so on.

ADJ n - where n represents the number of words that could appear between your keywords/phrase, e.g. middle ear adj4 infect* would search for the phrase "middle ear" within 3 words (or fewer) of the word infection, infectious, etc

Retrieving:

middle ear infection

infected middle ear

infection of the middle ear

middle-ear derived infections, and so on.

CINAHL (EBSCO platform)

Use N n - where n represents the number of word s that could appear between your keywords/phrase, e.g. "mid dle ear" N 3 infect*

Note that whilst the N proximity searching will find terms regardless of the order in which they appear, the Within operator (W) will find only those articles where the terms appear in the order they were entered. For example, typing kidney W3 failure will retrieve articles which include the phrases 'kidney failure'/'kidney transplant failure'/'kidney graft failure' but not 'failure of the kidneys'.

Web of Science

Use NEAR/ n - where n represents the number of word s that could appear between your keywords/phrase, e.g. "middle ear" NEAR/3 infect*

Using W/n restricts to n words between the two words; the word order is not set, e.g. pain W/5 morphine will retrieve 'pain controlled using morphine' as well as 'morphine to control pain'

Pre/n restricts to n words between the two words, but the word order is as set, e.g. newborn PRE/3 screening will retrieve 'newborn hearing screening' but not 'screening of the newborn'

Use NEAR/# or n/#

Finds documents where the search terms are separated by up to a certain number of words of each other (either before or after). Note: If you don't specify a number after the slash, NEAR will default to maximum 4 intervening words between terms

Example: computer NEAR/3 careers

computer and careers can be separated by up to 3 intervening words

retrieves career in the computer industry

See Proquest search tips library guide for more information

Subject headings and Keyword searching

Subject heading search

It is important when searching databases which have a thesaurus and which tag articles with subject headings (Medline, Embase, PsycInfo, Cinahl, etc) that your search strategy combines (with OR) both relevant subject headings and keyword/free-text searches on a particular concept. For full details see the Drawing up your search strategy tab .

In databases on the Ovid platform a subject heading search is shown with a / after the term:

drug hypersensitivity/

If the subject heading has been exploded to include narrower more specific terms then this will show with exp before it:

exp drug hypersensitivity/

If the subject heading has been focussed (limiting to articles where the selected subject heading is a major concept of the article) then this will show as:

*drug hypersensitivity/

exp * drug hypersensitivity/.

In CINAHL on the EBSCO platform you will see MH used to indicate that a subject heading has been searched; a + sign to indicate the subject heading has been exploded; and MM is used to indicate that the subject heading has been limited to results where this is a focussed/major concept of the article.

(MH "Wound Care") - subject heading search (MH "Wound Care+") - exploded subject heading search (MM "Wound Care+") - exploded and focusssed/major concept search.

The databases on the NICE HDAS platform use the same symbols as the Ovid platform databases above.

Keyword search

The default keyword search on databases on the Ovid platform is a multi-purpose search across several fields including title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier. This is shown as .mp search

In Cinahl the default keyword search is of the Title, Abstract and Subject headings fields.

In the NICE HDAS databases the default keyword search is of Title and Abstract.

It is possible to select a more specific keyword search on those databases that have a broader multi-purpose search as default - see the 'Searching in the Title and Abstract fields' box on this page.

Searching in the Title and Abstract fields

In the search strategies of some Cochrane reviews for searches undertaken on databases on the Ovid platform with subject headings/thesaurus trees, e.g. Medline, Cinahl, Embase, PsycINFO, and so on, you may notice that they use .tw when searching for keywords. This indicates a free text search in just the title and abstract fields.

Cochrane Ovid Medline asthma search strategy

The default in the Ovid databases is for a .mp search.

In order to carry out a free text search in just the title and abstract fields in Ovid you need to manually type in the letters .tw after your free text terms e.g. wheez*.tw in the search box. If you simply type in a search term it will default to the .mp search.

In Cinahl on the EBSCO platform you need to search for your terms in the Title and in the Abstract and OR these together:

appearing in the search strategy as

Using keyword searching limited to the Title and Abstract field should reduce the number of results which are retrieved in error or are only on the periphery of your subject. If you do this, please be aware that you will need to ensure that you have definitely also included all relevant subject headings in your search strategy otherwise you risk missing out on useful results.

Ovid Medline search strategy extract from:

Marcano Belisario, J.S., Huckvale, K., Greenfield, G., Car, J., Gunn, L.H. (2013), 'Smartphone and tablet self management apps for asthma', Cochrane Database of Systematic Reviews , Issue 11. Art. No.: CD010013. DOI: 10.1002/14651858.CD010013.pub2 .

As well as truncation other wildcards are available to use on some databases. These wildcards differ from database to database so it is worth checking (via their help pages) if you are looking for a particular function on a database platform.

OvidSP databases (e.g. Medline, Embase, PsycINFO)

Use # inside or at the end of a word to replace exactly one character, e.g. wom#n for women and woman.
Use ? inside or at the end of a word to replace zero or one character, e.g. robot? for robot OR robots, but not robotic; flavo?r for flavor OR flavour, but not flavours. Operators can be combined, e.g. an?emi* for anaemia OR anemia OR anaemic OR anemic
Note that $ can be used as alternative to * to indicate truncation in Ovid.
The question mark (?) represents any single character (rather than zero or one character in Ovid).
The dollar sign ($) represents zero or one character (rather than as an alternative to the * truncation as used in Ovid).
wom?n will search for women or woman
sawt??th will search for sawtooth and sawteeth

CINAHL (on EBSCO)

The wildcard is represented by a question mark ? or a hash [pound] sign # .

For example, type ne?t to find all citations containing neat , nest or next (net would not be retrieved).

# wildcard replaces 0 or 1 character.

For example, type colo#r to find all citations containing color or colour.

Phrase searching

When developing your search strategy you may wish to search using specific phrases rather than simply undertaking a search on individual keywords combined with OR. For example searching for "physical therapy" as a phrase in the title or abstract of articles will limit your search significantly compared to searching for 'physical OR therapy'.

Most database platforms use double quotation marks "..." to ensure that keywords are searched as a phrase. (NB phrase searching is the default in databases on the Ovid platform).

Examples of phrase searching include:

"physical therapy"

"lung cancer"

"cognitive behavioural therapy"

Phrase searching can sometimes be too restrictive so do bear in mind that some databases also allow you to use proximity searching (see the box on this page).

The screenshots below show the difference in the number of results when using phrase searching compared to OR keyword searching.

Ovid Medline

Double quotes “ ” will search for fuzzy phrases, i.e. terms which are similar. It will also search for both singular and plurals (with some exceptions). Symbols are ignored. Wildcards can be used. “heart-attack” will search for heart-attack, heart attack, heart attacks, and so on.
Curly brackets { } will search for a specific phrase. It limits the search to only the specified character string, and symbols can be used. {heart-attack} will only search for heart-attack.
Requires the use of double quotation marks " " to ensure words are searched as a phrase rather than the database doing an AND search with your terms.

Use NOT in a search to narrow your search and exclude keywords or subject headings from your search.

The NOT command allows you to search for terms that appear in the results of Search B (blue shaded area in the diagram above) but not in the results of Search A. It limits your results by excluding particular aspects of your initial search.

In most databases you have to type the NOT search line in as there is no button to select to combine using NOT.

On both the OvidSP platform and NICE HDAS platform you simply type in the search line numbers around NOT, e.g. 1 NOT 2. In CINAHL on the EBSCO platform you need to type in the relevant Search ID (see the column to the left of the Search Terms) around the NOT command, e.g. S1 NOT S2. Scopus requires you to use 'AND NOT' to perform a NOT search.

Common uses of the NOT command in systematic reviews:

The Cochrane Handbook recommends using the NOT command as part of their search strategy to filter out Animal only studies (part of the RCT filter). This is a search optimised for the Medline database on the Ovid platform.

1) Your combined search terms

2) exp animals/ not humans.sh.

3) 1 not 2

Search line 2 limits results to animal only studies and search line 3 then excludes these from the results when combined with your search terms.

See See Section 3.6 Search Filters of 4.S1 Technical Supplement to Chapter 4 [of the Cochrane Handbook for Systematic Reviews of Interventions]: Searching for and selecting studies.

In the search above the results have been limited to articles which have been tagged with the focussed subject heading of Pregnancy (and narrower more specific terms as it has been exploded) and then animal only studies have been excluded. This double use of NOT (in search line 2 and 3) as opposed to just using the human limit (a tick box under the limits option) is to ensure articles which may have been tagged with both animal and human are returned as well as human only studies.

NOT searching can also be used to exclude particular publication types, e.g. letters or editorials. See the Using Filters tab for more information.

Use NOT with care as used incorrectly it may exclude results that you are interested in. For example, if you were interested in retrieving research on the use of antidepressants in treating depression and excluded the terms CBT OR cognitive behavioural therapy using NOT then you would also exclude any results which directly compared the two methods. If you do wish to use NOT to exclude specific keywords or subject headings then consider adapting the Cochrane method for excluding animal only studies using the double use of NOT.

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So you want to do a systematic review
What Review is Right for You?
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Cochrane Handbook Chapter 4: Searching for and selecting studies
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Disclaimer: While we are happy to advise on developing systematic review searches, we may not have the capacity to create or perform the search for you.

Identify databases (minimum 3) and search terms needed to find all relevant literature. Consider meeting with a librarian. Conduct searches including unpublished/grey literature. Record numbers in PRISMA flow chart.

Identify databases and search terms

Identify databases to conduct your search

You should plan to search at least 3 databases. Most reviewers expect to see Medline (either via PubMed or Ovid) as one of the databases for health topics. Additional databases should be included based on your subject area. For a list of all available databases, consult the USF Health Libraries A to Z database list.

Identify search terms to conduct your search

Searches for a systematic review need to be both comprehensive (prioritizing sensitivity over specificity) and reproducible . To make your search comprehensive, identify both key words and controlled vocabulary to describe the main concepts of your question.

Develop search strategies for each database

Combine terms using appropriate Boolean operators and subject headings (if applicable) for every database. Searches should be as similar as possible between the database.

Consider meeting with a librarian

No matter how experienced you are in searching PubMed and the medical literature, you will likely need help creating a search strategy that meets the guidelines for evidence synthesis in the health sciences. In fact, both the Cochrane Handbook and the Institute of Medicine recommend including a librarian trained in systematic review searching on your team.

While this may not be possible, you may wish to consult with a librarian early in the process to ensure that you do not miss critical terms and databases in your search. Once you have developed your search strategy, you may also wish to request that a librarian conduct a peer review of your strategy. This will ensure that your review is in compliance with Peer Review of Electronic Search Strategies (PRESS) guidelines for systematic reviews.

Make a Systematic Review Consult appointment with a librarian Set up an appointment to meet with a health librarian. Select Systematic Review Consult and upload your protocol. This will ensure that your appointment time is most effective. Please note that a systematic review consult does not mean that the librarian is automatically a part of your systematic review team.
PRESS Peer Review of Electronic Search Strategies: 2015 Guideline Statement McGowan J, Sampson M, Salzwedel DM, Cogo E, Foerster V, Lefebvre C. PRESS Peer Review of Electronic Search Strategies: 2015 Guideline Statement. J Clin Epidemiol. 2016;75:40-46. doi:10.1016/j.jclinepi.2016.01.021

Conduct searches

Run each search in the databases you selected, documenting your search strategy for each one. You should include these in your manuscript, typically as an appendix.
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Record numbers in a PRISMA flowchart

The PRISMA diagram shows the flow of records through the phases of a systematic review. It maps the number of records identified, included and excluded, record sources, and the reasons for exclusions. Different templates are available depending on the type of review (new or updated) and sources used in the review.

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Published: 22 August 2022

Transparency of reporting search strategies in systematic reviews

K. M. Saif-Ur-Rahman 1 , 2 , 3 , 4

Hypertension Research volume 45 , pages 1838–1839 ( 2022 ) Cite this article

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The Original Article was published on 08 August 2022

Systematic reviews are considered the highest level of evidence, as they provide precise information that is essential for decision making at different levels. Searching databases for the literature is one of the fundamental components of a systematic review [ 1 ]. A poor search strategy may lead to low-quality evidence. The recently published systematic review by Zhang et al. [ 2 ] highlighted the association between altitude and the prevalence of hypertension among permanent highlanders. The authors demonstrated methodological robustness in all aspects of the systematic review except for the search strategy. The authors provided two search strategies as supplementary material. Search 1 yielded 1035 citations from MEDLINE (through PubMed) after applying the search date restrictions mentioned by the authors (from inception to April 30, 2021). Search 2 yielded 1204 citations in MEDLINE (through PubMed) after applying the same filter for the date. Interestingly, the authors mentioned in the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) flow diagram that the total number of retrieved articles is 1273, and 694 of them were retrieved from PubMed. This mismatch certainly calls into question the transparency of the review. It seems that the authors failed to report the search strategy transparently to make it replicable. Another issue is that the authors did not provide a comprehensive search strategy for all the databases that they searched (MEDLINE/PubMed, Embase, and Web of Science).

The PRISMA statement [ 3 ] provides the standard norms for reporting a systematic review and meta-analysis. The PRISMA 2020 [ 4 ] statement is the latest updated guideline that specifically recommends that authors should provide the full search strategies for all databases, registries, and websites searched. Systematic reviews should be reported in a way so that they can be replicated and updated to add to the evidence base. For transparent reporting, the presentation of the comprehensive search strategy with all filters applied is essential. The Peer Review of Electronic Search Strategies (PRESS) guidelines have provided a comprehensive direction for developing search strategies for systematic reviews and health technology assessment reports [ 1 ]. The checklist for the PRESS guidelines included the translation of the research question into population, intervention, comparison, and outcome elements; the use of Boolean and proximity operators; the use of database-specific subject headings, text word or free text searching, considerations of spelling, syntax, and line numbers; and limitations and filters. The PRESS guidelines involve the peer review process of the search strategy. However, even if the review is not peer-reviewed, developing search strategies in accordance with the PRESS guidelines is very useful.

The use of artificial intelligence (AI) enhances the robustness of the systematic review process and overcomes resource constraints [ 5 ]. The systematic review accelerator program provides support in developing and refining search strategies with the help of AI. The “search refiner” is a tool that supports understanding the formulation of search strategy, visualizing, and use of Boolean queries. The tool also helps to refine the search queries in more effective ways [ 6 ]. Another interesting tool of the systematic review accelerator is the Polyglot Search Translator [ 7 ], which supports the translation of the search strings across different databases. The use of AI can thus help to develop search strategies efficiently and effectively. This will also support the authors in reporting the search strategies transparently and increase the reliability of the process undertaken. Systematic reviews should be conducted following standard methods to avoid bias in the review process. Standard systematic reviews may provide strong evidence for clinicians, policymakers, researchers, and end users. Systematic reviews conducted without following standard methods and reporting guidelines may lead to waste of research and are simply considered “garbage in and garbage out”. Journals should be strict in requiring that authors perform systematic reviews in accordance with established robust methods.

McGowan J, Sampson M, Salzwedel DM, Cogo E, Foerster V, Lefebvre C. PRESS Peer Review of Electronic Search Strategies: 2015 guideline statement. J Clin Epidemiol. 2016;75:40–6. https://doi.org/10.1016/j.jclinepi.2016.01.021

Article PubMed Google Scholar

Zhang Y, Yang Y, Wu X, Han B, Mao A, Gu D, et al. The association between altitudes and the prevalence of hypertension among permanent highlanders. Hypertens Res. 2022. https://doi.org/10.1038/s41440-022-00985-2

Moher D, Liberati A, Tetzlaff J, Altman DG. PRISMA Group Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6:e1000097. https://doi.org/10.1371/journal.pmed.1000097

Article PubMed PubMed Central Google Scholar

Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71 https://doi.org/10.1136/bmj.n71

Clark J, Glasziou P, Del Mar C, Bannach-Brown A, Stehlik P, Scott AM. A full systematic review was completed in 2 weeks using automation tools: a case study. J Clin Epidemiol. 2020;121:81–90. https://doi.org/10.1016/j.jclinepi.2020.01.008

Scells H, Zuccon G. searchrefiner: a query visualisation and understanding tool for systematic reviews. Proceedings of the 27th ACM International Conference on Information and Knowledge Management. 2018;1939–42.

Clark JM, Sanders S, Carter M, Honeyman D, Cleo G, Auld Y, et al. Improving the translation of search strategies using the Polyglot Search Translator: a randomized controlled trial. J Med Libr Assoc. 2020;108:195–207. https://doi.org/10.5195/jmla.2020.834

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Acknowledgements

The author acknowledges the different systematic review method groups.

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Evidence Synthesis Ireland and Cochrane Ireland, University of Galway, Galway, Ireland

K. M. Saif-Ur-Rahman

College of Medicine, Nursing and Health Sciences, University of Galway, Galway, Ireland

Health Systems and Population Studies Division, icddr,b, Dhaka, Bangladesh

Department of Public Health and Health Systems, Nagoya University Graduate School of Medicine, Nagoya, Japan

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Saif-Ur-Rahman, K.M. Transparency of reporting search strategies in systematic reviews. Hypertens Res 45 , 1838–1839 (2022). https://doi.org/10.1038/s41440-022-01003-1

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Received : 05 July 2022

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Published : 22 August 2022

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DOI : https://doi.org/10.1038/s41440-022-01003-1

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Related Guides

A guide to conducting reviews.

A guide prepared by Ms. S. Nalbandian targeted to outline some of the common types of reviews including literature, systematic, and scoping reviews, and lists some ways by which University Librarians can assist in conducting such reviews.

Limit to Humans

To exclude animal studies while doing a systematic review, different databases require different search strategies. The below show these strategies according to the database used:

Medline - OVID : the below two lines work well to exclude animal studies in Medline, use either one:

FinalResult NOT (Animals/ NOT (Animals/ AND Humans/))

FinalResult NOT (exp animals/ not humans.sh.)

PubMed: below search strategy in PubMed will exclude animal studies from the final result:

FinalResult NOT ("Animals"[Mesh] NOT ("Animals"[Mesh] AND "Humans"[Mesh]))

OVID Embase:

FinalResult NOT ((exp animal/ or nonhuman/) NOT exp human/)

Embase.com:

FinalResult NOT ([animals]/lim NOT [humans]/lim)

Exclude Medline Results from PubMed

To get PubMed records not in Medline : FinalResult NOT medline [sb]

Note : since there can be a slight time lag in getting from PubMed to Medline, it may also be worth searching PubMed for anything added in the past two or three days.

Hedges or Filters by Study Design

After running a search strategy on resources such as Medline/Pubmed, use any of below validated filters/hedges (developed to balance precision and recall) to limit search to RCT, Systematic Reviews, etc...

Cochrane Collaboration under part 2, section 6.4.11
Scottish Intercollegiate Guidelines Network (SIGN)
InterTASC ISSG Search Filters
McGill Comlete Guide
Health Information Research Unit at McMaster
BMJ Best Pracice
University of Texas School of Public Health
University of Alabama
Your Own Private Librarian
ASTED search strings
PubMed Search Strategies
OVID Expert Searches

Harvard search filters for systematic reviews

University of Alberta Subject Filters created a number of subject filters such as pediatrics , geriatrics , cancer , religion , end-of-life , social media , telehealth etc...

Topic search filters: a systematic scoping review. Raechel A. et al. Health Information & Libraries Journal 36(1):4-40, First Published 21 December 2018

Low and Middle Income Countries (LMIC) filter from Cochrane

Advice: Don't limit by study methodology unless you have to!

This is because in most cases, such limits result in missing relevant studies due to 1) large variety of terms used to describe study types 2) many authors never mention methodologies in title/abstract 3) inconsistent indexing in particularly for non-randomized designs.

If retrieved results are unmanageable and you need a methodology filter, use validated filters that have been tested against gold-standard sets.

Some Hedges

Systematic Reviews
Qualitative

Medline OVID filter from Cochrane - Max Sensitivity: ((randomized controlled trial.pt. or controlled clinical trial.pt. or randomized.ab. or placebo.ab. or drug therapy.fs. or randomly.ab. or trial.ab. or groups.ab.) not (exp animals/ not humans.sh.))

Medline OVID filter from Cochrane - Max specificity: ((randomized controlled trial.pt. or controlled clinical trial.pt. or randomized.ab. or placebo.ab. or clinical trials as topic.sh. or randomly.ab. or trial.ti.) not (exp animals/ not humans.sh.))

PubMed filter from Cochrane- Max Sensitivity: (randomized controlled trial [pt] OR controlled clinical trial [pt] OR randomized [tiab] OR placebo [tiab] OR drug therapy [sh] OR randomly [tiab] OR trial [tiab] OR groups [tiab]) NOT (animals [mh] NOT humans [mh])

PubMed filter from Cochrane - Max Specificity: (randomized controlled trial[pt] OR controlled clinical trial[pt] OR randomized[tiab] OR placebo[tiab] OR clinical trials as topic[mesh:noexp] OR randomly[tiab] OR trial[ti]) NOT (animals [mh] NOT (humans [mh] AND animals[mh]))

EMBASE.com filter from Cochrane: 'crossover procedure':de OR 'double-blind procedure':de OR 'randomized controlled trial':de OR 'single-blind procedure':de OR (random* OR factorial* OR crossover* OR cross NEXT/1 over* OR placebo* OR doubl* NEAR/1 blind* OR singl* NEAR/1 blind* OR assign* OR allocat* OR volunteer*):de,ab,ti

EMBASE.com filter from SIGN: 'clinical trial'/de OR 'randomized controlled trial'/de OR 'randomization'/de OR 'single blind procedure'/de OR 'double blind procedure'/de OR 'crossover procedure'/de OR 'placebo'/de OR 'prospective study'/de OR 'randomi?ed controlled' NEXT/1 trial* OR rct OR 'randomly allocated' OR 'allocated randomly' OR 'random allocation' OR allocated NEAR/2 random OR single NEXT/1 blind* OR double NEXT/1 blind* OR (treble OR triple) NEAR/1 blind* OR placebo*

CINAHL filter from SIGN: TX allocat* random* OR (MH "Quantitative Studies") OR (MH "Placebos") OR TX placebo* OR TX random* allocat* OR (MH "Random Assignment") OR TX randomi* control* trial* OR TX ( (singl* n1 blind*) OR (singl* n1 mask*) ) OR TX ( (doubl* n1 blind*) OR (doubl* n1 mask*) ) OR TX ( (tripl* n1 blind*) OR (tripl* n1 mask*) ) OR TX ( (trebl* n1 blind*) OR (trebl* n1 mask*) ) OR TX clinic* n1 trial* OR PT Clinical trial OR (MH "Clinical Trials+")

PsycINFO filter from ProQuest: SU.EXACT("Treatment Effectiveness Evaluation") OR SU.EXACT.EXPLODE("Treatment Outcomes") OR SU.EXACT("Placebo") OR SU.EXACT("Followup Studies") OR placebo* OR random* OR "comparative stud*" OR clinical NEAR/3 trial* OR research NEAR/3 design OR evaluat* NEAR/3 stud* OR prospectiv* NEAR/3 stud* OR (singl* OR doubl* OR trebl* OR tripl*) NEAR/3 (blind* OR mask*)

Web Of Science (WoS) filter from University of Alberta - Not Validated:

TS= clinical trial* OR TS=research design OR TS=comparative stud* OR TS=evaluation stud* OR TS=controlled trial* OR TS=follow-up stud* OR TS=prospective stud* OR TS=random* OR TS=placebo* OR TS=(single blind*) OR TS=(double blind*)

SCOPUS filter from Children's Mercy Kansas City, copy/paste into 'advanced search':

TITLE-ABS-KEY((clinic* w/1 trial*) OR (randomi* w/1 control*) OR (randomi* w/2 trial*) OR (random* w/1 assign*) OR (random* w/1 allocat*) OR (control* w/1 clinic*) OR (control* w/1 trial) OR placebo* OR (Quantitat* w/1 Stud*) OR (control* w/1 stud*) OR (randomi* w/1 stud*) OR (singl* w/1 blind*) or (singl* w/1 mask*) OR (doubl* w/1 blind*) OR (doubl* w/1 mask*) OR (tripl* w/1 blind*) OR (tripl* w/1 mask*) OR (trebl* w/1 blind*) OR (trebl* w/1 mask*)) AND NOT (SRCTYPE(b) OR SRCTYPE(k) OR SRCTYPE(p) OR SRCTYPE(r) OR SRCTYPE(d) OR DOCTYPE(ab) OR DOCTYPE(bk) OR DOCTYPE(ch) OR DOCTYPE(bz) OR DOCTYPE(cr) OR DOCTYPE(ed) OR DOCTYPE(er) OR DOCTYPE(le) OR DOCTYPE(no) OR DOCTYPE(pr) OR DOCTYPE(rp) OR DOCTYPE(re) OR DOCTYPE(sh))

SCOPUS filter from National University of Singapore:

( INDEXTERMS ( "clinical trials" OR "clinical trials as a topic" OR "randomized controlled trial" OR "Randomized Controlled Trials as Topic" OR "controlled clinical trial" OR "Controlled Clinical Trials" OR "random allocation" OR "Double-Blind Method" OR "Single-Blind Method" OR "Cross-Over Studies" OR "Placebos" OR "multicenter study" OR "double blind procedure" OR "single blind procedure" OR "crossover procedure" OR "clinical trial" OR "controlled study" OR "randomization" OR "placebo" ) ) OR ( TITLE-ABS-KEY ( ( "clinical trials" OR "clinical trials as a topic" OR "randomized controlled trial" OR "Randomized Controlled Trials as Topic" OR "controlled clinical trial" OR "Controlled Clinical Trials as Topic" OR "random allocation" OR "randomly allocated" OR "allocated randomly" OR "Double-Blind Method" OR "Single-Blind Method" OR "Cross-Over Studies" OR "Placebos" OR "cross-over trial" OR "single blind" OR "double blind" OR "factorial design" OR "factorial trial" ) ) ) OR ( TITLE-ABS ( clinical trial* OR trial* OR rct* OR random* OR blind* ) )

Medline OVID filter from SIGN: ((Meta-Analysis as Topic/ or meta analy$.tw. or metaanaly$.tw. or Meta-Analysis/ or (systematic adj (review$1 or overview$1)).tw. or exp Review Literature as Topic/ or cochrane.ab. or embase.ab. or (psychlit or psyclit).ab. or (psychinfo or psycinfo).ab. or (cinahl or cinhal).ab. or science citation index.ab. or bids.ab. or cancerlit.ab. or reference list$.ab. or bibliograph$.ab. or hand-search$.ab. or relevant journals.ab. or manual search$.ab.) or ((selection criteria.ab. or data extraction.ab.) and review/)) not (comment/ or letter/ or editorial/)

PubMed filter for systematic reviews, metaanalysis and health technology assessment from CADTH:

systematic[sb] OR meta-analysis[pt] OR meta-analysis as topic[mh] OR meta-analysis[mh] OR meta analy*[tw] OR metanaly*[tw] OR metaanaly*[tw] OR met analy*[tw] OR integrative research[tiab] OR integrative review*[tiab] OR integrative overview*[tiab] OR research integration*[tiab] OR research overview*[tiab] OR collaborative review*[tiab] OR collaborative overview*[tiab] OR systematic review*[tiab] OR technology assessment*[tiab] OR technology overview*[tiab] OR "Technology Assessment, Biomedical"[mh] OR HTA[tiab] OR HTAs[tiab] OR comparative efficacy[tiab] OR comparative effectiveness[tiab] OR outcomes research[tiab] OR indirect comparison*[tiab] OR ((indirect treatment[tiab] OR mixed-treatment[tiab]) AND comparison*[tiab]) OR Embase*[tiab] OR Cinahl*[tiab] OR systematic overview*[tiab] OR methodological overview*[tiab] OR methodologic overview*[tiab] OR methodological review*[tiab] OR methodologic review*[tiab] OR quantitative review*[tiab] OR quantitative overview*[tiab] OR quantitative synthes*[tiab] OR pooled analy*[tiab] OR Cochrane[tiab] OR Medline[tiab] OR Pubmed[tiab] OR Medlars[tiab] OR handsearch*[tiab] OR hand search*[tiab] OR meta-regression*[tiab] OR metaregression*[tiab] OR data synthes*[tiab] OR data extraction[tiab] OR data abstraction*[tiab] OR mantel haenszel[tiab] OR peto[tiab] OR der-simonian[tiab] OR dersimonian[tiab] OR fixed effect*[tiab] OR "Cochrane Database Syst Rev"[Journal:__jrid21711] OR "health technology assessment winchester, england"[Journal] OR "Evid Rep Technol Assess (Full Rep)"[Journal] OR "Evid Rep Technol Assess (Summ)"[Journal] OR "Int J Technol Assess Health Care"[Journal] OR "GMS Health Technol Assess"[Journal] OR "Health Technol Assess (Rockv)"[Journal] OR "Health Technol Assess Rep"[Journal]

'meta analysis'/exp OR 'systematic review'/exp OR (meta NEAR/3 analy*):ab,ti OR metaanaly*:ab,ti OR review*:ti OR overview*:ti OR (synthes* NEAR/3 (literature* OR research* OR studies OR data)):ab,ti OR (pooled AND analys*:ab,ti) OR ((data NEAR/2 pool*):ab,ti AND studies:ab,ti) OR medline:ab,ti OR medlars:ab,ti OR embase:ab,ti OR cinahl:ab,ti OR scisearch:ab,ti OR psychinfo:ab,ti OR psycinfo:ab,ti OR psychlit:ab,ti OR psyclit:ab,ti OR cinhal:ab,ti OR cancerlit:ab,ti OR cochrane:ab,ti OR bids:ab,ti OR pubmed:ab,ti OR ovid:ab,ti OR ((hand OR manual OR database* OR computer*) NEAR/2 search*):ab,ti OR (electronic NEAR/2 (database* OR 'data base' OR 'data bases')):ab,ti OR bibliograph*:ab OR 'relevant journals':ab OR ((review* OR overview*) NEAR/10 (systematic* OR methodologic* OR quantitativ* OR research* OR literature* OR studies OR trial* OR effective*)):ab NOT (((retrospective* OR record* OR case* OR patient*) NEAR/2 review*):ab,ti OR ((patient* OR review*) NEAR/2 chart*):ab,ti OR rat:ab,ti OR rats:ab,ti OR mouse:ab,ti OR mice:ab,ti OR hamster:ab,ti OR hamsters:ab,ti OR animal:ab,ti OR animals:ab,ti OR dog:ab,ti OR dogs:ab,ti OR cat:ab,ti OR cats:ab,ti OR bovine:ab,ti OR sheep:ab,ti) NOT ('editorial'/exp OR 'erratum'/de OR 'letter'/exp) NOT ('animal'/exp OR 'nonhuman'/exp NOT ('animal'/exp OR 'nonhuman'/exp AND 'human'/exp))

CINAHL filter from SIGN:

(MH "Meta Analysis") OR TI meta analys* OR AB meta analys* OR TI Metaanaly* OR AB metaanalys* OR (MH "Literature Review+") OR TI systematic review* OR AB systematic review* OR TI systematic overview* OR AB systematic overview* NOT (PT commentary OR PT letter OR PT editorial OR MH animals+)

ProQuest PsycINFO filter from Leicester University Hospitals

TI,AB,IF((comprehensive* OR integrative OR systematic*) NEAR/3 (bibliographic* OR review* OR literature)) OR TI,AB,IF((meta-analy* or metaanaly* or "research synthesis" or ((information or data) NEAR/3 synthesis) or (data NEAR/2 extract*))) OR TI,AB,IF(review NEAR/5 (rationale or evidence)) and ME("Literature Review") OR AB(cinahl or cinhal or (cochrane NEAR/3 trial*) or embase or medline or psyclit or psychlit or pubmed or scopus or "sociological abstracts" or "web of science") OR ME("systematic review" or "meta analysis")

For more info read An optimal search filter for retrieving systematic reviews and meta-analyses

Medline OVID filter from CADTH:

exp clinical pathway/ or exp clinical protocol/ or exp consensus/ or exp consensus development conference/ or exp consensus development conferences as topic/ or critical pathways/ or exp guideline/ or guidelines as topic/ or exp practice guideline/ or practice guidelines as topic/ or health planning guidelines/ or (guideline or practice guideline or consensus development conference or consensus development conference, NIH).pt. or (position statement* or policy statement* or practice parameter* or best practice*).ti,ab,kf,kw. Or (standards or guideline or guidelines).ti,kf,kw. Or ((practice or treatment* or clinical) adj guideline*).ab. or (CPG or CPGs).ti. or consensus*.ti,kf,kw. Or consensus*.ab. /freq=2 or ((critical or clinical or practice) adj2 (path or paths or pathway or pathways or protocol*)).ti,ab,kf,kw. Or recommendat*.ti,kf,kw. Or (care adj2 (standard or path or paths or pathway or pathways or map or maps or plan or plans)).ti,ab,kf,kw. Or (algorithm* adj2 (screening or examination or test or tested or testing or assessment* or diagnosis or diagnoses or diagnosed or diagnosing)).ti,ab,kf,kw. Or (algorithm* adj2 (pharmacotherap* or chemotherap* or chemotreatment* or therap* or treatment* or intervention*)).ti,ab,kf,kw.

Pubmed filter from CADTH:

Clinical pathway[mh] OR Clinical protocol[mh] OR Consensus[mh] OR Consensus development conferences as topic[mh] OR Critical pathways[mh] OR Guidelines as topic [Mesh:NoExp] OR Practice guidelines as topic[mh] OR Health planning guidelines[mh] OR guideline[pt] OR practice guideline[pt] OR consensus development conference[pt] OR consensus development conference, NIH[pt] OR position statement*[tiab] OR policy statement*[tiab] OR practice parameter*[tiab] OR best practice*[tiab] OR standards[ti] OR guideline[ti] OR guidelines[ti] OR ((practice[tiab] OR treatment*[tiab]) AND guideline*[tiab]) OR CPG[tiab] OR CPGs[tiab] OR consensus*[tiab] OR ((critical[tiab] OR clinical[tiab] OR practice[tiab]) AND (path[tiab] OR paths[tiab] OR pathway[tiab] OR pathways[tiab] OR protocol*[tiab])) OR recommendat*[ti] OR (care[tiab] AND (standard[tiab] OR path[tiab] OR paths[tiab] OR pathway[tiab] OR pathways[tiab] OR map[tiab] OR maps[tiab] OR plan[tiab] OR plans[tiab])) OR (algorithm*[tiab] AND (screening[tiab] OR examination[tiab] OR test[tiab] OR tested[tiab] OR testing[tiab] OR assessment*[tiab] OR diagnosis[tiab] OR diagnoses[tiab] OR diagnosed[tiab] OR diagnosing[tiab])) OR (algorithm*[tiab] AND (pharmacotherap*[tiab] OR chemotherap*[tiab] OR chemotreatment*[tiab] OR therap*[tiab] OR treatment*[tiab] OR intervention*[tiab]))

Medline OVID Filter from University of Texas

((("semi-structured" or semistructured or unstructured or informal or "in-depth" or indepth or "face-to-face" or structured or guide) adj3 (interview* or discussion* or questionnaire*))).ti,ab. or (focus group* or qualitative or ethnograph* or fieldwork or "field work" or "key informant").ti,ab. or interviews as topic/ or focus groups/ or narration/ or qualitative research/

CINAHL filter from University of Alberta

qualitative OR ethnol* OR ethnog* OR ethnonurs* OR emic OR etic OR leininger OR noblit OR "field note*" OR "field record*" OR fieldnote* OR "field stud*" or "participant observ*" OR "participant observation*" OR hermaneutic* OR phenomenolog* OR "lived experience*" OR heidegger* OR husserl* OR "merleau-pont*" OR colaizzi OR giorgi OR ricoeur OR spiegelberg OR "van kaam" OR "van manen" OR "grounded theory" OR "constant compar*" OR "theoretical sampl*" OR glaser AND strauss OR "content analy*" OR "thematic analy*" OR narrative* OR "unstructured categor*" OR "structured categor*" OR "unstructured interview*" OR "semi-structured interview*" OR "maximum variation*" OR snowball OR audio* OR tape* OR video* OR metasynthes* OR "meta-synthes*" OR metasummar* OR "meta-summar*" OR metastud* OR "meta-stud*" OR "meta-ethnograph*" OR metaethnog* OR "meta-narrative*" OR metanarrat* OR " meta-interpretation*" OR metainterpret* OR "qualitative meta-analy*" OR "qualitative metaanaly*" OR "qualitative metanaly*" OR "purposive sampl*" OR "action research" OR "focus group*" or photovoice or "photo voice" or "mixed method*"

Embase.com filters from McMaster University

Maximizes sensitivity: interview*:ab,ti OR qualitative:ab,ti OR ‘health care organization’/exp

Maximizes specificity: qualitative:ab,ti OR ‘qualitative study’:ab,ti

Best balance of sensitivity and specificity: interview*:ab,ti OR ‘health care organization’/exp OR experiences:ab,ti Source: Embase.com format of HiRU (Health Information Research Unit), McMaster University, Ontario, search strategies .

Scopus filter from University of Alberta

TITLE-ABS-KEY(qualitative OR ethnol* OR ethnog* OR ethnonurs* OR emic OR etic OR leininger OR noblit OR "field note*" OR "field record*" OR fieldnote* OR "field stud*" or "participant observ*" OR "participant observation*" OR hermaneutic* OR phenomenolog* OR "lived experience*" OR heidegger* OR husserl* OR "merleau-pont*" OR colaizzi OR giorgi OR ricoeur OR spiegelberg OR "van kaam" OR "van manen" OR "grounded theory" OR "constant compar*" OR "theoretical sampl*" OR glaser AND strauss OR "content analy*" OR "thematic analy*" OR narrative* OR "unstructured categor*" OR "structured categor*" OR "unstructured interview*" OR "semi-structured interview*" OR "maximum variation*" OR snowball OR audio* OR tape* OR video* OR metasynthes* OR "meta-synthes*" OR metasummar* OR "meta-summar*" OR metastud* OR "meta-stud*" OR "meta-ethnograph*" OR metaethnog* OR "meta-narrative*" OR metanarrat* OR " meta-interpretation*" OR metainterpret* OR "qualitative meta-analy*" OR "qualitative metaanaly*" OR "qualitative metanaly*" OR "purposive sampl*" OR "action research" OR "focus group*" or photovoice or "photo voice" or "mixed method*")

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Last Updated: Nov 25, 2023 4:40 PM
URL: https://aub.edu.lb.libguides.com/SML-Systematic_Review

IMAGES

Search string within the systematic literature review.
Search string used for the systematic literature review
Search strings used in the systematic literature review.
Flow-chart for the systematic review. Search string: "migraine AND
Where to search?
A practical guide to question formation, systematic searching and study

VIDEO

新手如何起步寫論文丨寫論文實戰技巧丨 Systematic review and meta-analysis 系統性回顧與統合分析丨impact factor收集系列 @EBSCOTaiwan
Unlocking the Power of Large Language Models for Search String Development
Constructing Systematic Review Search in PubMed CDS
General search for health research literature
What are the alternatives to a systematic review?
Search strategy level two

COMMENTS

How to carry out a literature search for a systematic review: a
A literature search is distinguished from, but integral to, a literature review. Literature reviews are conducted for the purpose of (a) locating information on a topic or identifying gaps in the literature for areas of future study, (b) synthesising conclusions in an area of ambiguity and (c) helping clinicians and researchers inform decision-making and practice guidelines.
Research Guides: Systematic Reviews: Search Strategy
Creating a Search Strategy. A well constructed search strategy is the core of your systematic review and will be reported on in the methods section of your paper. The search strategy retrieves the majority of the studies you will assess for eligibility & inclusion. The quality of the search strategy also affects what items may have been missed.
Step 3: Develop a Systematic Review Search Strategy
Related systematic reviews can help you generate search terms and identify databases and journals of relevance to your topic. In addition, viewing the citations of those reviews might help you identify relevant research. Many databases include search filters or limiters that will limit your search to just systematic reviews.
Systematic Reviews and Meta-Analyses: How to Search
In a systematic review and/or meta-analysis, the search should collect all potentially relevant material that is available. In other words, the search must be comprehensive. Though exact strategies will vary according to where you search, you can start by designing a base search strategy by following these steps: Identify important concepts.
4. Search Terms & Strategies
Systematic Reviews: Constructing a Search Strategy and Searching for Evidence from the Joanna Briggs Institute provides step-by-step guidance using PubMed as an example database. General Steps: Locate previous/ relevant searches. Identify your databases. Develop your search terms and design search. Evaluate and modify your search.
How to write a search strategy for your systematic review
4. Manage the search results. Once the search is done and you have recorded the process in enough detail to write up a thorough description in the methods section, you will move on to screening the results. This is an exciting stage in any review because it's the first glimpse of what the search strategies have found.
Building your search string
Search fields When you enter your basic search string into the search bar, your search terms will generally be checked to see if they appear anywhere in the text of the article. This can potentially create a lot of noise. Limiting your search to a to specific search fields will make it more focused.
Building Search Strategies
To illustrate each step for developing a search strategy, the example used in the following 11 steps is (with a slight adaptation): Aromataris, E & Riitano, D 2014, 'Systematic reviews: Constructing a search strategy and searching for evidence', AJN The American Journal of Nursing, vol. 114, no. 5, pp. 49-56.
Developing a Search Strategy
Image: Pinterest Techniques for search term harvesting. Begin brainstorming search terms by using the following techniques: Explore gold standard articles supplied by the principal investigator or found through preliminary searches.; Look at search strategies from published systematic reviews.; Scan records, articles, and searches for usable controlled vocabulary and natural language.
Searching
Systematic review search strings can be incredibly complex. This is why it is fundamental to have an information specialist on the research team. For an example of a systematic review search strategy, please examine the document below to see additional information from M.D. Anderson Cancer Center Library.
Systematic Reviews and Meta-Analyses: Where to Search
In a systematic review, you do not determine the relevance of references in the database itself. Instead, download all references yielded by your search into a citation manager. This process allows for more transparency as the exact yield (count and content) from the comprehensive search is documented and the process for determining relevance ...
Library Guides: Systematic Review: Developing a search strategy
Select your keywords carefully. Check against inclusion/exclusion criteria. Repeated testing is required to create a robust search strategy for a systematic review. Run your search on your primary database and evaluate the first page of records to see how suitable your search is. Identify reasons for irrelevant results and adjust your keywords ...
Systematic Reviews: Step 3: Conduct Literature Searches
When you decide to update a systematic review search, there are two ways of identifying new articles: 1. Rerun the original search strategy without any changes. Rerun the original search strategy without making any changes. Import the results into your citation manager, and remove all articles duplicated from the original set of search results.
A systematic approach to searching: an efficient and complete method to
INTRODUCTION. Librarians and information specialists are often involved in the process of preparing and completing systematic reviews (SRs), where one of their main tasks is to identify relevant references to include in the review [].Although several recommendations for the process of searching have been published [2-6], none describe the development of a systematic search strategy from ...
Step 3: developing a search strategy
Study types: 'systematic reviews', 'RCT' (randomised control trials) Age groups: 'children', 'elderly' They are available to select via the results filters displayed alongside your results. For instance, on PubMed after running your results it is possible to limit by 'Ages' which gives predefined groupings such as 'Infant: birth-23 months'.
Systematic Reviews
Systematic review search strings can be incredibly complex. This is why it is fundamental to consult an information specialist (librarian). For an example of a systematic review search strategy, please examine the document from M.D. Anderson Cancer Center Library. Example Search String in 3 Databases.
Advanced search techniques
Common uses of the NOT command in systematic reviews: The Cochrane Handbook recommends using the NOT command as part of their search strategy to filter out Animal only studies (part of the RCT filter). This is a search optimised for the Medline database on the Ovid platform. 1) Your combined search terms. 2) exp animals/ not humans.sh. 3) 1 not 2
Systematic Reviews: Constructing a Search Strategy and Searc... : AJN
A number of other search-field descriptors can be used as well, such as [au] for "author" and [pt] for "publication type." 2 Using a search-field descriptor such as [tw] ("text word") is often preferred over [tiab] for systematic reviews because the former searches in the title and abstract of articles as well as across a greater ...
Search
Identify search terms to conduct your search; Searches for a systematic review need to be both comprehensive (prioritizing sensitivity over specificity) and reproducible. To make your search comprehensive, identify both key words and controlled vocabulary to describe the main concepts of your question. Develop search strategies for each database
Step 3: Develop a Systematic Search Strategy
Turning a research question into a search string is a multi-stepped process: Break down your research question into searchable concepts; ... During the planning stage, it is recommended that the team searches for existing systematic and scoping reviews on related topics. This helps to ensure that you are not duplicating an existing review (a ...
An automated approach to identifying search terms for systematic
When writing a search string for a systematic review, researchers will often want to use stemming to capture additional word forms because it makes the search string more efficient (Bramer, Jonge, Rethlefsen, Mast, & Kleijnen, 2018). For example, a search string to capture articles about fledglings should use the stemmed term fledg* because the ...
Search strategy formulation for systematic reviews: Issues, challenges
In this review, we focus on literature searching, specifically the development of the search strategies used in systematic reviews. This is a complex process ( Cooper et al., 2018 ; Lefebvre et al., 2020 ), in which the search methods and choice of databases to be used to identify literature for the systematic review are specified and peer ...
Transparency of reporting search strategies in systematic reviews
Another interesting tool of the systematic review accelerator is the Polyglot Search Translator , which supports the translation of the search strings across different databases. The use of AI can ...
Search Filters / Hedges
ASTED search strings; PubMed Search Strategies; OVID Expert Searches; See also: Harvard search filters for systematic reviews University of Alberta Subject Filters created a number of subject filters such as pediatrics, geriatrics, cancer, religion, end-of-life, social media, telehealth etc... Topic search filters: a systematic scoping review.
Full article: A Systematic Review of the Limitations and Associated
This systematic review aims to address this gap by critically examining existing empirical studies on ChatGPT. 3. Method. ... " AND "limitations," along with synonyms such as "weakness," "drawback," "challenge," and "pitfall" (for detailed search strings, refer to Appendix A). For establishing inclusion and exclusion criteria, ...
Vaccines
The systematic review of PubMed, CINAHL, and Embase identified 2562 articles, and 56 articles met all inclusion criteria and were included in this scoping review. A majority of the reviewed studies investigated some combination of knowledge, attitudes, behaviors, and beliefs about HPV and the HPV vaccine in students in professional programs ...

Systematic Reviews

Developing an Answerable Question

Validated Search Filters

Why Create a Sensitive Search?

Systematic Reviews

Designing Your Search Strategy

How to write a search strategy for your systematic review

Practical tips to write a search strategy for your systematic review

Pro Tip – Talk to your librarian and do it early!

2. Write and refine the search

3. Run and record the search

4. Manage the search results

And you’re done!

Laura Mellor. Portsmouth, UK

Top 5 Tips for High-Quality Systematic Review Data Extraction

How to get through study quality assessment Systematic Review

How to extract study data for your systematic review

Better systematic review management

Building your search string

Combining keywords with Boolean operators

More tips and suggestions

Minilecture Smart search

Useful links and resources

[anchornavigation]

University of Tasmania, Australia

Building Search Strategies

Steps of Building Search Strategies

Templates / Helpsheets

Additional Resources

Need More Help? Book a consultation with a Learning and Research Librarian or contact [email protected] .

Systematic Review

Developing a Search Strategy

Workshop materials

Errors in search strategies

Further readings

Hedges by Topic (in alphabetical order )

Systematic Reviews

Search Strings

The Exhaustive Search

Study types and other considerations

Hand Search

1. Clarification of the data

3. New developments

Caveats for searching

Systematic Reviews and Meta-Analyses: Where to Search

Where to search

Identifying Relevant Databases

Searching Databases

Downloading Results from Databases

Download Limits

Study Registries & Preprint Archives

Online Resources

Web search engines and specific websites

Resources for web browsing

Citation Searching

How to citation search?

Personal Contacts

Predatory Journals

Predatory Journals in Systematic Reviews

Systematic Review

Being systematic

Identify the key concepts in your research question

Identify search terms

Example keywords table:

Recommendations:

Google Scholar

Other sources of grey literature

Systematic Reviews: Step 3: Conduct Literature Searches

About Step 3: Conduct Literature Searches

Search the FAQs

Reporting your review with PRISMA

Managing your review with Covidence

How a librarian can help with Step 3

Search Process

Identify search concepts and terms for each

View our example in PICO format

View Controlled Vocabulary for our example PICO

Keyword Terms

Display Controlled Vocabulary and Keywords for our example PICO

Boolean operators